...I find it strange for people being able to beat the casino since this in theory it is totally impossible in the long run.
We should not deny the fact that there are professional players in this industry who, thanks to their card counting skills, regularly win at casinos. And this is the biggest expense item, and accordingly, the casino makes every effort to identify such players with a further ban on casino gaming.
I don't know if you've ever been to a real casino, where you are monitored 24/7 and you are not free to do anything, simply if you win too much you are out, either you cheat or not, you count cards or not, they catch you and throw you out, you can be the best card counter in the world but if you are inconvenient they cut you out