I understand what you're saying and that's really one of the ways to gain those good referrals. Especially if you're a good writer and the blog that you've written is helpful to them and you've attached the referral link onto that article or blog that you've written.
And as you gain them, you're also building a network and making a community out of them, that's a good idea and if you're consistent with that then congratulations to you.
Not all does really have able to sustain themselves or getting successful specially on affiliate marketing or ways or methods of earning money because it is really that rare on earning something from your referrals.
Out of all the years on my gambling career or activity which i didnt intend or had just tried up on spreading links but havent get a single person who signed up under my link which is something i do lost interest.
About most rewarding crypto casino then it wouldnt vary or differ much specially on most known or popular ones.They do offer or do mimic out to each other.
It's not rare in the other industry, affiliate marketing is one of the best passive incomes. And one of the examples of it is from the online shopping economy. The industry of it has gotten big and wider so affiliate marketing isn't rare there.
But for the online gambling industry, yeah, it could be said that it's quite rare that someone earns a lot from it. Well, who knows what will be the turn for the next years to come.