I think casinos are not regulated just to retain fiat payment methods or those users, but rather to prevent money laundering. Sometimes we see issues of money laundering even against regulated casinos, so at least the government may be regulating casinos as necessary to prevent money laundering.
Yes, it is possible to remain non-certified and non-regulated, but ask yourself how many uncertified casinos do you feel comfortable gambling at without any hesitation? This is why casinos are currently being regulated as necessary.
Actually an unregulated casino has more chances of getting into an exit scam than a regulated casino, from what I feel. But this might not always be true.
We can understand that the objective is to control money laundering but often people who are looking for anonymity are flocking in crypto based casinos and thus their effort is counter-productive.
There is also the question of many casinos being used for offshore trading and there are fiat based casinos who are involved in it but everyone gives it no attention.