Given that this is kingdom hearts and multiple worlds exist in that franchise and its possible to travel between them it’s possible to have 'travel the world without leaving your home" and still make it so that the full game is only playable with GPS location. All they’d have to do is tie physical locations to worlds in game but then make those worlds navigable without requiring the user to move.
Not just that, but they get to charge $100 dollars more for the $5 of ROM while avoiding the support costs and reputation hit of idiots who force the SD card in the wrong way or blaming the device when the SD card is inevitably sheered in half after being forgotten about during a battery replacement.
Unfortunately every market incentive just aligns against expandable storage in phones.