Vitek: This thing I'll never get.
When I have some games on several platforms I never touch them on some and only play them on one, so why should I feel more incentive to get it on 2 platforms instead of one. I wouldn't variate between playing them anyway.
It doesn't matter. When I can buy something for one platform and then the other one gives it to me for free, where the other option is to buy it on one platform and only have it there, it's suboptimal to buy it on the platform where I will not get the free version. The discussion of rewarding the devs, some exclusive preorder bonuses and whatnot (Steam'll probably have that as well tho, just different ones) nonwithstanding, the entire issue boils down to one thing: One approach gets me copy of the game on one service, the other approach gets it on two. If anything happens to the alternate service provider, I will always be able to rely on the other one.