...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.
If I understand correctly, card counting is a prohited style of gambling across several online casinos, even physical casinos as well, and what this means is that if you as a gambler engage in it, it simply means you are carrying out a fraud, which is why the casino won't hesitate to ban and even sanction the user once he or she caught.
We here are not talking about beating a casino through dubious means, but through gambling legitimately and adhering to every single rules that applies to game you choose to play, any body can commit fraud and beat the casino several times over time as long as they are not caught, but when it comes to gambling legitimately, it's possible to beat the casino in the short term, but very difficult to stay and continue beating the casino in the long run, this is as good as impossible though.