They provide services that use blockchain technology and blockchain networks for transactions (deposits, withdrawals) and I am sure those blockchains have public ledgers so that everyone can trace transactions including casinos.

Casinos don't need to have licenses to trace blockchain transactions of users. However if they register licenses and have to obey with rules for KYC/ AML, they must have some terms about AML and more powerful tools to detect money laundering activities through cryptocurrency transactions on their casinos.