One of my issues with all of these game developers opting to create a coin for every new game that are developed, comes with the limitation of the utility for these tokens. You can basically only use those tokens in that game and there are no real demand for that token for anything else.
you can trade these tokens on an exchange . the tokens nature is on video games so it's normal that the tokens will only be used this way . We can't say that these tokens will also be used on the mainstream market but there are tokens that are also built for that .It would be nice if you could get some platform like this where gamers could swap/trade coins into tokens that are more useful. You could farm tokens in a game that are easier to farm and convert those tokens into a game token where those tokens are more difficult to acquire. It would create a more streamlined market for these tokens, if a platform like this existed. 
This is possible and I saw many concept like this where you can trade inside the game . About farming/earning tokens inside a game , i like that too but I don't think they will allow it because that will only lead to abuse and gamers will only depend on it instead of buying the tokens .