@Edent yes!!! I can’t find the thread now but I was discussing this exact idea with… I think it was @tijs and @zverik a few months ago. I have no dev time to devote for it now but happy to chat if you’d like to swap ideas.
In particular, I think one raison d’être for such an app (aside the obvious utility which obviously many of us got from 4sq) is to gamify submitting and verifying POIs in OSM. With a good UX and some careful thought, I’m optimistic it could really improve OSM for POIs.