Those big wins they do show during streems sometimes to me does look like it was planed between them and some of these casinos so I do consider them to be unrealistic because how is it that other regular gamblers find it hard to replicate on theioqn end, it's just have to be some manipulations since the casinos have got access to the back end.
It depends on games. If the casino could manipulate their operations and machineries just for a couple of people, their reputation and credibility gets questioned. But those who stream are definitely doing something to make it seem like they are profiting a lot during their time in the casino and I am sure that the casino is aware of doing that and are even encouraging or paying streamers for to manipulate the content.