As Bitcoin gets more attention, more online casino operators would not want to miss the opportunity to tap the crypto gaming market. Existing operators that cater to only fiat-money players would consider accepting Bitcoin, while new brands in iGaming would launch as crypto-friendly casino and sports betting sites, for instance. Gaming dApps, for instance, may also get the boost they need to launch and get a strong following and support from the community.
As you mentioned the gambling sites that caters only fiat currency will see the changing trend and they might start accepting bitcoin, even not you can deposit money using third party services but you need to convert to fiat.
Bitcoin is freedom and if the sites that accept bitcoin to gamble and does not ban users from some countries it would be better, asking KYC if you think that they tried to defraud is once aspect but banning countries is well against the bitcoin ethics and if every gambling sites follow these everything will flourish.