Casino running through "decentralized" system is always without KYC  no matter is old casino or new. Because, they're running without human activity and most the time are on-chain transaction. The disadvantage playing on decentralized casino are:
- Limited Game
- The betting activity quite complicated, since you need to each transaction everytime you want to do betting

However, the advantage playing on these  type casino you're free (KYC). A long time ago, there has some casino sportsbook decentralized same like these but the odds are terrible comparing to centralized casino.