The biggest difference easily overlooked is the cross-buy entitled customers to
multiple versions of the same game on multiple platforms. With Smart Delivery, customers will play the
only version of the game across multiple SKUs that will smartly scale accordingly. This also guarantees cross-saves and DLC support, something cross-buy lacked since the games were technically different from one another. If you have a Series X in your living room and a Xbox One upstairs, you can play the 4K version of your game downstairs during the day, then retire to play the Xbox One version upstairs, all with the same save etc.
For instance, between PS3 and PS4, I owned Black Flag and with cross-buy upgraded to the PS4 version. However, I was forced to start from the beginning of the game due to the fact they were two separate versions of the same game. Smart Delivery eliminates this and makes for a far more elegant implementation.
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