Magic is a full-fledged, complex and slow card game; if that's your thing, you'll love it. It has decades of cards with unique mechanics and rules, and you can spend a whole year reading about the game and there will be still plenty of stuff to learn.
MtG is so traditional and huge that it became "the game" to be beaten in the Collectible Card Game market, much like World of Warcraft became "the game" to be beaten in the MMORPG market.
But the truth is that it doesn't have to be beaten; there's enough players for different games in the same niche. Gods Unchained, for example, is SO similar to MtG that it's obvious that it's just trying to mimic (and beat) it... is this needed? I don't think so.
Splinterlands, in the other hand, tried something different, and created a more-casual, more newbie-friendly game that's (way) faster to play and simple enough to be played on mobile phones. It's still a collectible card game, but it has its own ideas and game mechanics.