A game than can be monetize using cryptocurrency always being a good ideas. If only bitcoin manage to get users to play bitcoin it will create a mass adopt to a lot of gamer user. There was a lot of project that using cryptos in their project but a lot has being never survive for the first year as their was not of a new user that willing to use cryptos in game.
Sadly, most of the mobile games are monetised one way, gamers buys several staff from game developers. Probably there is no use to put bitcoin payment option that such games. Who would love to pay bitcoin for game bonuses via fiat>bitcoin>game, when in most games you can get same result paying directly from card? Doubt that there are even a lot gamers among cryptocurrency users.