I am sure businesses, both banks and casinos, see rakeback/Cashback as a investment. They purposely give up on part of their income or profits, so in the long term they get even more money.
One think is the fake perception people have on those perks, as of they were getting money for free from casinos, and a different thing is what actually happens in the book-keeping of casinos and banks. In reality, rakeback and Cashback prompts people to spend more and gamble more and that is what matters in the eyes of those businesses.
There is still a lot to learn about how the Rakeback and Chasback schemes work, but the two are different, because the advertised rates are the same and the calculation base is different.
Each casino has a policy that will certainly be different, casinos that already have high credibility may give both rakeback and cashback that are equally profitable,
both for players and for the casino, but for casinos that have no credibility and are completely illegal, I doubt about the rakeback or cashback programs they provide, and of course the percentages will be different.
I found a full explanatory article on the difference between Rakeback and Cashback and it might be helpful about the detailed explanation.
https://www.rakeback.com/news/casino-cashback-vs-rakeback/