If there's one thing the cloud fixes that I am definitely appreciative of, it's that I don't have to re-buy my game if the disc breaks.
Now I don't tend to abuse my discs; I try to take good care of them. But accidents happen, and things can go wrong. Just last week I noticed that one of my games has a large crack in the middle (where there is no coding). I don't recall ever abusing that disc, and yet the crack is there, and if the crack ever extends any further out, that game is going to be useless, and I would need to buy a new copy if I ever wanted to play the game again.
With the Xbox One, that problem is gone, because I can play the game without the disc. Once I've installed the game and gotten my digital copy stored in the cloud, I won't need to worry about any damage done to the disc, because I can still play my game from any X1 in the world. That is a real benefit.
