Will, there comes a time that all online gambling sites will be Cryptocurrency based?
No, fiat based ones would still exist no matter what because there would be always players who do prefer on playing fiat based rather than on considering crypto.
We know that there are people who dont totally trust on how crypto works and they dont really care at all and by means of security they do highly believe on what fiat-based online casinos have the edge.
Fiat based gambling sites will still exist but we can't really say that crypto based gambling sites will not exist in the future because cryptocurrency is becoming popular nowadays and who know someone will create a gambling site that is cryptocurrency based. Also, not all people prefer using fiat in gambling sites because it is complicated unlike when you use crypto it is more secure.
People don't trust crypto because they don't understand how it works and they only believe what they hear or see and not really knowing the benefits of using cryptocurrency in gambling sites. All gambling platforms or even casinos are all the same regardless if you use cryptocurrency or fiat.