I heard some higher officials including security people to mingle into gamblers like other gamblers to watch any kind of breach and then signal to control room if anything unusual happens. I have not seen any such people doing but I guess it could be another thing might be happening on physical casino just to ensure their environment go intact. From all these I just conclude running a physical casino is not a simple business rather than that, I may go simply owning an online casino.
I think that the presence of such employees depends on the size and profitability of the casino. The larger the casino, the more serious and professional its security service is. I think the biggest casinos in Las Vegas and that's where the best security services in the world are.
For me, as a player, the main thing is that I can enjoy the game and no one interfered with it.
When it comes to gambling places then these kind of problems like rage, argumentation with co-players and other stuff does exist but only on a rare numbers.
Security is a must when it comes to these kind of establishments which is normal because we dont know on when do problem arise that do really needs security intervention
and the rest is just part of the norm on where it is just right for them to place out these personnel for anyones safety.