Why not just use binary saves, and have the user copy the save data you give them.
Should roblox implement your idea, Yes, but only with the places of the same owner, so that you avoid clashes, ie: one place saves 'temp', and so does a completely other place, these will be overwritten unintentionally, and so some data may be lost
Implementing with places of the same owner also reduces lag, as you don't need to load ALL the saves on your character, but only those of your character for the games of the owner of the place you are in |