There is nothing wrong bringing people to gambling platform to earn rewards like you earning referral rewards too. There are crypto platforms that give high rewards to gamblers for referral which is another way to increase the numbers of gamblers and it is usually embraced by new gambling platforms that are in need of customers.
Usually, the casino site will not stop giving bonuses to new and old members and the casino gives these bonuses regularly to attract new members. Old members can also be more motivated to find new members by using their referrals because the bonuses they get can be even greater. But usually, people, after joining a gambling platform, will further research whether the casino is the casino they are looking for or not. And if that's the casino they want, they'll stay in that casino and play for a long time.
I think that the importance of referral links for the development of a crypto-casino business is not too great. The fact is that only one of your friends out of 20 or 30 of those invited by you through a referral link can then become a regular player.
Nevertheless, even such methods of stimulating the search for customers are still used, though it seems to me not too much.