This isn't unique and really it never works. Game developers will just create their own coin/token and make more off of it then using XAYA. If I create a virtual world game, I'll create my own coin to go with that game.
You sure can do it - but then you also have to set up your own blockchain, get miners to secure that (one-game) blockchain, maintain a robust cryptocurrency network and a lot of other things that are not related at all to your game. So why would you actually do all that (assuming that you even have the required blockchain knowledge to pull it off)?
Xaya is a platform and unique blockchain made specifically for games. Unlike many other projects, it is
not just a Bitcoin clone that claims to be "a cryptocurrency for games" without actually having any game-specific features.