This has always been this way even in FFXI (to certain point) if player A wanted to play XI on PS2 they buy the game and register the key only thing different with XI then with XIV is you could just borrow the PC discs from a friend and then log into your account on PC without having to buy the game again. This is not the case with XIV player A account needs to buy a key for each system they want to play on. Now where XI and XIV are the same is if player B wants to play they can't borrow player As disc and install and just play (just setting up a sub) they would have to buy the game also to get the key as well as buy the game (key) again for each system they want to play on.