In general, almost all streamers with big online have affiliate programs with casinos, I also thought that they bet their own money, but at some point I saw this article https://last-gamer.com and learned a lot about casino streaming. But I wouldn't say it's a scam, it's more like an advertisement. Similarly, there are streamers who have affiliate programs with games. Another thing is if they advertise casinos that are scammers, then this is also a scam, but Twitch bans casinos that do not have a license.