You are asking if a game is better designed on a central database, a distributed database, or a blockchain.  It all depends on your audience, your reputation, your game design and your reward method.  Not too complicated. 

All those things come down to trustworthiness.  If you are EA Games, and you have a million players following your game development you can probably get away with a centralized database, even if you deal in a non-reversable currency.   But if you are a nobody in the game world, and you want to deal with cryptocurrency, at the very minimum you'll want to design rewards that can be tracked.  Doesn't have to be on a non-changeable blockchain - as long as an invested player feels he can monitor corruption, he will feel some trust and you can put the data on a database he/she can look at.   But if you have a proprietary game (no source code) and you play with crypto - game economics are better handled on a blockchain.