I have worked for a few years in a casino and I couldn't help but imagine that people should be able to gamble with bitcoin
Truth be told, I've never been to a real casino
I mean a real one, not some room with slot machines and similar stuff. But from what I know (okay, from what I've seen in the movies) people don't use cash there directly. Casinos use gaming chips, i.e. small discs used instead of paper money and coins. Then you can redeem the chips (provided you have any left, of course) for real cash. To me, Bitcoin would be cumbersome to exchange these chips for in these circumstances
There are already tons of casino games that we could play using crypto you only need to know the website.
And there are also some people who use some online games to gamble and have fun for example tongits go and other kinds of apps too
OP asks about real casinos (think Las Vegas here)
People use a huge pile of cash on slots, chips are used on gaming tables (poker, blackjack, live roulette, etc..). Yeah usually in movies they show you gaming tables and chips.