I dont think you need to support multiple games, but a dev with a similar game could say that some other NFT from some other competitor game will unlock equivalent items in my game, so come on over and jump ship! Competition of eyeballs. Expecially if those NFT are not in some walled garden and built on a common platform. You could then trade NFT's from one game for NFT's in another. I'll trade you my zucker-verse penthouse for a unique ship in Eve Online!

Yes, a dev could screw with interpretation, but that would likely create a lot or angry people and kill your cash cow as they move on. Zuck makes your pentouse smaller you are going to be pissed.