I would play this app if they had one for Death Angel, but I'd hate to see the app overshadow the hardcopy game. It'd be nice for quick easy single player, but in my opinion the game really does shine when you get a bunch of people playing it together, interacting. Although some people may be turned onto the game through the app, sometimes you run the risk of people only playing the app version.
For me, I'd love the app because I'm on the road a lot, and often have time to kill where I can't bring the game itself. So for this, the app would be great. But for me, it'd never come close to getting together with a group and playing the actual game.