From a tweet by Alber Microsoft Paintbrush we confirm the presence on Xbox One a feature already present on the Xbox 360, yet poorly understood: as a result of the purchase of a digital title on Xbox One you can download the single use license, and then the whole game, if the same has already been installed previously on the hard disk (because maybe had borrowed from a friend).

This feature, perhaps unimportant on Xbox 360, could prove critical to those who would take a title in Digital Delivery but are "scared" by the size of downloads: sufficient to lend the game from a friend, install it and then making your purchase on Game Store to have it ready for use without having to wait for a very long download. What can I say, we have to find a friend who will pay your favorite game!