With your thread I can say that you strongly believe in Fiat currency than crypto currency and I don't know the reason for your decisions but crypto is better as pertaining the privacy and security but you don't get that with regular fiat casinos which is why you need to trust online crypto gambling and talking about coins not having value,how about trying stable coins and see the outcome.
He may have many experiences playing gambling using fiat currency than crypto currency. But that will be up to him and other people because there is no forcing for any people to playing gambling using fiat or crypto currency.
If they feels better to use fiat and still use fiat, they can use fiat and not to use crypto. But as we knows crypto can be used to playing gambling, we choose to use crypto to playing gambling because we can hides ourselves.
Maybe he needs to try to use crypto to playing gambling so he knows what's it feels and maybe he will like to use crypto than fiat too like us. Using stable coin is the other options for those who doesn't wants to use bitcoin or altcoin while they can buy the stable coin and send it to their gambling account.