The tactile nature of the touchscreen and the easy way you can hook up with people online has made mobile a natural home for a variety of card games.
Naturally that includes those ever-laying golden geese, collectable games.
For all the pretenders that have come and gone, Magic: the Gathering remains the undisputed champion of the genre. And, of course, it has a mobile version: Duels of the Planeswalkers.
That app is designed as a gateway drug, offering a slice of the colossal collection of real-life cards to enjoy, to tempt new players to take up the physical product.
But Blizzard wasn't content to let the champ have it its own way. Its offering, Hearthstone (based loosely on a 2006 physical game which rejoiced in the title World of Warcraft Trading Card Game), went the whole hog. It ditched the material game completely, and put it all online.
At first, this sounds nuts. One of the big draws of collectable gaming is collecting things, and having a tangible stack of cardboard. Things you can sleeve, display, caress with your fingertips, and hopefully watch accrue in value as editions go out of print.
Blizzard, however, didn't become a multi-million dollar behemoth without being smart. It understood this and gave you an awful lot of Hearthstone for nothing. The game is free, and as long as you play regularly you can accumulate enough in-game currency for more free cards.
The initial spike is sharp and awkward. In spite of a good tutorial, your initial battles with your tiny card set against real-world opponents can be brutal. And the tutorial doesn't entirely explain how you unlock the rest of the basic cards, and start earning expert ones.
But if you can crest that wave, and start tearing open those virtual boosters, Hearthstone well and truly has you by the short and curlies.
Because one of the other big draws of collectable gaming is the excitement of opening packs. The anticipation, not knowing what's going to be inside that crinkly shrink, is tangible. So is the elation, or disappointment, at your new acquisitions.
The beauty of Hearthstone is that you can get that same junkie high for free, just by earning in-game gold. And once you're hooked, well, it's only a tiny outlay to buy an extra pack. Then you're on the value slide toward buying multipacks to get more for your money.
Before you know it, you've spent more than the cost of a full-price console game. But you can still get that hit for free. So the cycle continues.
Naturally, there's enormous crossover between the two communities. One of the first to draw direct comparisons between the two was Magic champion and game designer Brian Kibler, who'd worked on that old Warcraft Trading Card game.
His take, published during the open beta of the game, was that although Hearthstone was fun and made good use of multimedia to present and teach the game, it was spoiled by the class powers.
The rationale was that predictable abilities interfered with the collectable format by defining the play more than the cards you choose for your deck.
That was true in the beta, and it's still true now. But I would argue that it's not as limiting as he makes out. While synergising cards with your hero power is an important part of deck building, players generally focus far more on cards than powers. There are several ways of making an effective deck for most classes, and the differences between the powers only really come to the fore in long matches where hands run low.
The big names in Hearthstone have been somewhat more reticent with opinions of their rival. But I talked to Andrey Yanyuk, perhaps better known by his Hearthstone handle of Reynard, to find out what he thought.
"They have a lot of similarities" he told me. "But there's a key game design difference in the resource system."
"In Magic, about 40 percent of your deck is land, your mana resource," he explained. "Since the amount you draw is variable, some games you end up only playing a few cards due to lack of lands. Equally, if the majority of cards you draw are lands, you have no options for most of the game."
Any Magic player will quickly confirm the truth of this. The former situation even has an in-game nickname: "mana screwed".
Yanyuk was keen to contrast the mechanics of Hearthstone. "Its mana system is consistent," he said. "You gain one per turn up to ten, so every card you draw is a minion or spell. That's the number one reason I feel Hearthstone is a better designed game."
Having laid his cards on the table, so to speak, Yanyuk was happy to put the boot in a bit further.
"The other key difference is combat", he continued. "In Magic, the defender determines which attacking and defending creatures fight each other, giving them the advantage."
"In Hearthstone," he continued, "the player on offense can dictate which creatures fight each other, giving the player on offense the advantage in combat. This can lead to very 'snowbally' games."
I presume he means this as a complement to Blizzard's game. Personally I love the tactical options afforded by being able to choose my targets, and the thrill of unleashing a massive damage combo on my opponent.
Yanyuk is, however, keen to give Magic its due. "Blocking only applies to formats before the year 2012," he told me. "A key part of modern card design is punishing blocking while encouraging attacking as much as possible."
"This avoids clogged-up board states where neither player can attack, making the Magic limited format more appealing to newer players."
For me, this is another crucial point: Hearthstone is just faster and more furious than Magic, which makes for quicker matches and a smoother mobile experience.
Yanyuk took up the theme. "Magic has a phase-based system," he said. "You draw your card in the draw step, play your creatures in the main phase, and attack in the combat phase. In Hearthstone, you can sequence your plays in any way you want during your turn."
"It's a more intuitive system than in Magic," he continued. "But offers a bit less depth. In Magic you can play effects during your opponent's turn, which makes combat more exciting. When you make an attack in Hearthstone, you will usually know the outcome."
For me, this gets at the root difference between the two formats. Hearthstone is a far more streamlined game. Magic feels clumsy by comparison, but the result of that extra baggage is considerably richer strategy.
However, what none of the people I canvassed had much to say about was how the games differed in their mobile offering. Here, Hearthstone has a crucial advantage because it's built for mobile, whereas Magic is ultimately trying to shift physical product.
As a result, Hearthone pulls out all the stops to be an incredible digital experience. On top of the multimedia that Kibler praised, it does things you simply never could in a card-based game. Tracking damage on individual creatures, playing secrets, and offering a wide range of random effects would, at best, be so awkward in a physical game as to effectively rule them out.
Magic, by contrast, is tightly constrained by its tabletop origin. For all its merits, it feels slow and plodding on mobile. Its publishers focus on the original version means less attention was paid to the app, resulting in poor performance and a weak interface.
The biggest barrier to Magic's success on mobile, however, is simply its need to not compete with its big brother by offering all the cards.
Magic's tabletop card library is enormous. While Hearthstone's comparatively limited selection feels comfortingly manageable at first, it does result is a fairly narrow range of play styles. In all the years I've been playing tabletop Magic, I've been consistently surprised by how often new approaches to building an effective deck come out.
Duels of the Planeswalkers has only a miniscule fraction of the available cards. Otherwise gamers might - shock, horror - start playing the game online rather than face to face, and physical sales would plummet.
Magic, as a product, is better than Hearthstone. It has more variety, and more depth.
But for us, as mobile gamers, there's no comparison. Hearthstone is more exciting, more accessible, better looking and by far the superior app. And as long as Wizards of the Coast rely on tabletop Magic as a cardboard cash cow, that's not going to change.