It occurred to me because when I signed up at a new casino, the odds of winning were quite high. I didn't know if it was just coincidence or if it was designed to win. After using the same account for a while, the win rate decreased. I excluded sports betting.
I have never had such an experience with crypto casinos, but for fiat slot sites, I have had such an experience. At first, I was very difficult to get a big multiplier with an old slot site. But a friend gave advice to register a new account with another site, I tried it, and got a pretty good multiplier on the first deposit.
Maybe that's what many say about casinos giving winnings at the beginning to make customers happy. But I don't know the truth because now I rarely access casino games.