Sometimes there are actions in games that require two or more datastore keys to be updated simultaneously, and to not execute unless both can succeed.
One usecase for this feature is developing a system for two players to trade items from their separate datastore entry inventories. I want to update both of their inventories at the same time, or not at all. The safest, most reliable way to do this would be if we had this new method for datastores. Not only is it more safe, it is also a ton less work than trying to write a safe edgecase handler for when trades fail in lua.