if a game publisher uses a CEX to exchange the crypto they receive from users into fiat and direct bank account deposit the fees can range from 0% to 0.6%
The only reason the fees are that low right now is because crypto is speculative, and users have no protections. If crypto is useful and buyers expect to be able to do things like refunds or charge backs the fees will do up to cover those costs.
Looking at how crypto works right now and suggesting it'll still be the same if people use it as currency is silly.