Well, nowadays majority of the crypto gambling websites offer instant withdrawals,so I doubt this is priority for crypto gambling community. There were more anonymous casinos or bookies few years ago while it is hard to find reliable gambling platform nowadays. Promotions are important to bring more customers as first step btw.
And actually that is the saddest part also nowadays as while all of casinos offers instant deposit and withdrawal yet cases like holding fund's and banning accounts happens because after a player won big amount? Gambling site wil require this and that and will end up the players not getting his funds and ending to be scamming.