I don't think it's just about whether you're allowed to get a gambling license in your incorporating country, it's also whether you have a license to provide your service in users' countries as well. Certain countries e.g. UK can block certain casinos from operating there, while for others it is completely blocked for all casinos.
I disagree that casinos are treated like other fiat(-handling crypto) businesses, because of the inherent age restrictions of gambling, which results in tighter regulations on the gambling industry.
Yeah, so you need a license for each country that you intend on operating in. For example, if you want to supply to UK residents then you need a license to reflect that. This is where it gets complicated, because I know in the USA multiple states have a ban on gambling, right? Therefore, you need to block those users to the best of your ability, otherwise you might find yourself in legal issues. Obviously, the most logical steps would be blocking IPs that originate in those states, you can't really counteract against users that are using VPNs to bypass it.
Age restrictions will apply. For most licensed gambing websites you'll need to verify your age if you want to withdraw a certain amount. Most fiat gambling websites in the UK don't verify your age or identity until you withdraw a certain amount. Okay, the credit card will verify that you're at least of age to gamble, but not in every case, because you can get a debit card under the age of 18. Only certain gambling activities in the UK like the lottery are accessible to over 16s.
The idea of being licensed is; you'll require KYC from your customers. There is no two ways about it, if you want to become licensed, and therefore a legally operating gambling company, you will need to verify the age of your customers. Whether that's through cryptocurrency or fiat.
This isn't always the case depending on the license you have, and where you're operating from. Take a look at the gambling company that you use or if you don't use any just take a look at the most popular. I can almost guarantee in most instances they'll be operating offshore. It's one of the morally grey areas right now in the gambling industry, where companies base their company out of a country which has less regulations surrounding verifying who is using the website to gamble. They are usually operating in places which have less tax obligations too.