Microsoft’s Xbox One will allow you to access your entire games library, without needing to rely on discs according to information provided by Xbox Wire.
“After signing in and installing, you can play any of your games from any Xbox One because a digital copy of your game is stored on your console and in the cloud. So, for example, while you are logged in at your friend’s house, you can play your games.”
This also means that, you can purchase games either “at traditional retailers or online through Xbox Live, on day of release”. So no matter where you’re located, you can always be assured of getting the game – when it’s officially released in your region, of course.
However, accessing one’s game library from a different console is more complicated than that. As noted, “You can game offline for up to 24 hours on your primary console, or one hour if you are logged on to a separate console accessing your library.” Looks like Microsoft has all its bases covered insuring every user has a copy of the game on their own console, rather than leeching off their friends.