I don't know how the computer and the physical version align, but the physical 2015 set of Magic: the Gathering comes out on July 17th. This sale might be them getting their last hurrah in for the 2014 set. That won't make it less playable for someone just playing the computer version though I don't know how long the DLC packs will be available. Any M:tG Duels of the Plainswalkers 2013 players want to weigh in?
Each Duels of the Planeswalkers is entirely independent from the others, so the only thing you'd "Lose" with a new version coming out is presumably the majority of people who play in online matchmaker games would move to the new one. There's also no direct deck overlap between the games. There are some similar decks but no 1:1 duplicates. No need to be concerned about the older ones becoming obsolete unless you do a lot of multiplayer with strangers.
That said, they inexplicably no longer sell the first of the modern Duels of the Planeswalkers (the one from 2010. The real first DotP was '98) for whatever reason. Which is kind of a shame because out of all of them that one had the most iconic decks. Blue asshole control/discard, red burn, big green creatures, etc. The decks in the other games definitely aren't bad, it's just that none of them were as much the standard staple for each color.
Been talking an awful lot about cards today. On that topic I guess I'll say I played a little Dead Man's Draw. Not the same kind of card game as MTG or Hearthstone but seems enjoyable. Looks worth the $2.50.
It was $2 from Amazon for the complete pack during the Winter sale, hope you and everyone else picked it up despite all the DRM whining people had. It has a campaign, deck building, draft tournaments all SP or MP. It is not nearly as complex as MTG as far as cards, but can be more complex in terms of gameplay and metagaming. You can sit down and play a single game in just a few minutes. It is pretty much my goto quick time waster. And the devs continue to make slight balancing tweaks to the game.
Also this. Spectromancer's pretty good stuff. You don't do deckbuilding in it either (Not for reals deckbuilding at least) but it's a damn fine card game. Complexity's roughly above Hearthstone and under Magic. I'd definitely give a thumbs up to that one too.