Unlike lotteries as you said, casino is not 100% luck. I don't know how lotteries work, I haven't played on lotteries before but I see the shops and tenants around and I don't have idea how lotteries work. My take is that if these things are pure luck, one day someone needs to be lucky and rake the company.
When we are lucky enough we do excellently in casinos, you are right, the bad thing is when that luck runs out and that is when everything works out, referrals are something else, it is how a casino can reward a person that has many referrals, you must always have rules so that you can execute them, and they are always difficult to comply with, there are people who get involved and do tasks as well as airdrops and want to get the rewards for a while, but the rules may indicate that a referral or each referral has to deposit and play with a required amount and this is something that not everyone can meet.