Casino owners are already millionaires, but after releasing their tokens, they are aiming to become billionaires. 
Yes, you're right about that. We can only hope for a generous airdrop for the users of this forum. 
Basically, it's some sort of additional rakeback/cashback. We mine tokens by playing/wagering, and we can cash them out at any moment...
I wonder how other casinos exist without cashback in own token? Well, probably the easiest way is to give cashback in one of the cryptocurrencies integrated on the site (for example, bitcoin or solana).But, well, let's see what happens next. I don't mind, I'm just thinking...
Yeah I am surprised there isn't more casinos that do that.
Honestly it would be good to retain their users, and you know that casinos would eventually get that money back anyways if the gambler just kept gambling there. Why dont they do it? Maybe it would be too complex to implement.
I also think it would be a psychological thing in getting the player to keep wagering when in their back of their mind they know they will get some type of cashback token? And that token would be worth alot some day.