There are so many reasons NOT to.
Big reason is, if you deal with fiat, then you need to get licensed, you need to get regulatory approval, you need to prepare your entire system to work with a fiat system.
Do you honestly think you could enjoy low house edge, fast approvals, fast play, and all that, while using fiat systems? The whole reason dice games and crypto games can offer much lower house edge is because of lower operational cost. Choose to use fiat and kiss goodbye to those low operational costs.
I absolutely agree with slaman29, I would add a very important part it is anonymity and restrictions.
With crypto, you can play anonymously without any bank and personal data. Also, you can play in the country where is gambling prohibited.