Those must be scam casinos. If people, like streamers, promote a casino for free, not paying them is considered a scam. Therefore, it is highly advisable to avoid such casinos. Referring others to a casino is typically not an easy task. It also affects your reputation when you recommend someone to a particular website. So, be mindful of the casino you're directing your peers to.
You're right, if one must refer someone to a casino, then he must have gotten some oast experience in dealing with them than making a recommendation on what will tilt your own reputation you're having with those you're referring, it is true that so many casinos are rewarding for referal bonuses while some are just a pool of tricks to get traffic and not maintaining their promise for reward, we should have a good understanding of what we are promoting, those we are introducing into the promotional efforts and the possible risk that may comes in.
Do you know that some people refer people for a platform because of referral bonus not because they have knowledge of platform or they have win alot in particular gambling platform, why some people do so because they are comfortable with the operations of the gambling platform, everyone have it own reasons of recommending people of platform, it's not something we can agitating or arguing about, for the role of knowing what you are promoting, in normal sense you have to know your brand you are promoting so that you can explain it very well.