i dont call my self a pro but i can be a casual gambler . i dont check the license but i just play on the casino that i think not a scam . all of them are registered , they claim that within thier site . having these two is already enough and the place where it was registered is not a big deal to me but idk to some . if they are pro and big bettors , they probably care with it because they dont want to waste every bet they make . mostly the sites that i use are under curacao . curacao accept what they think is legit but they dont know if what happens next , the gambling site can do shady acts but curacao can always reverse the contract if found out so that their reputation will not be affected .
I heard about some casinos are hyping us about their curabao license, but to be honest, I am not impress with that as license is a basic requirement in order for them to operation, but reputation is the most important as it will be build along the way.
Some sites have good reputation, so if you'll ask me, I would not doubt anymore about their license, if they don't have, then they must be special for people to like them despite being unlicensed. Actually the word license should not be a big deal as we are in crypto, what we value is anonymity and license means we have to comply some regulation which would defeat the purpose of anonymity.