The Curacao license is the most popular because it has a much easier requirements and very convenient to get in able for your casino legally operate on many countries that there license is valid. Curacao is one of the early license provider on crypto gambling business that’s why it was the best choice for crypto casino. There’s other license provider but they have a very limited country scope which is not practical at all.
Curacao KYC is now adjusting based on the casino country origin because there license scope varies per country judicial rules about online casino.
In any case, the presence of a license indicates that the rights of players are somehow protected and their protection is provided by the regulator that issued the license. But for me personally, the greater protection is the fact that the casino has been operating since 2013. So the players need it.