So heres a thing.
This question assumes future in-app purchases, which we dont yet know if that will become a thing. Maybe all new content will be free or via physocal expansions.
Anyways, I imagine some people will flip between running the app on tablet and PC, for convenience or location.
So, if you purchased something through one platform (say pc) would the app be able to transfer to the other platform (say android).
Steam store and Google store I dont think interact easily.
Possibly single use serial code that would "unlock" the content on the other store?
Of course they may not charge for inn app stuff. Maybe you buy a room tile and get scenarios free with it or something.
Im just bouncing thoughts really.