Streamers work for money. If he get not enough money from stream - he get them from company. He can use money that he get due to contract, possible that casino gives him some money for gambling but i can`t call it "fake money" if he win - he got real money. How did he get it - it is another question and it isn`t about "fake money" as for me.
Or he use his referrals' income to gamble. Since there are million of subscribers and even more views, I believe he must make a huge amount of money reffering gamblers to casinos. In the end he uses this money to gamble on his videos without risking money from his own pocket. It's more like "free money" than "fake money". It's just a possibility, though. We can't confirm anything, because all the informations at our reach are purely speculative.
Oh, i just forget about the referrals. Surely he has huge quantity of referrals and big money from their gambling. And you right that it is "free" money. Or, possible, money that helps to increase income.
Anyway, i think, that it is out of my business where he gets money. And i prefer to think that it is real money until i see proves that it isn`t so.
If those are your views then that is fine with me, however I do care about the source of the funds of those streamers and that is because anyone that has ever gambled with play money knows, it is simply not the same, and that also is true when it comes to the person you are watching how they gamble, if they are given all of that money by a casino then all of that excitement they are supposedly feeling when they win or that sadness when they lose is fake, and if that is the case I might as well watch something else.