there are a lot casino's accept bitcoin. specially on a huge city
I can hardly find any place on this earth where you cannot use bitcoin. Bitcoin is the best thing this world has ever seen and is versatile in nature. You can use it anywhere you want it to be used. There are likely chances that bitcoin will be start using at casinos as well in near future. This will increase the market of bitcoin in a better way and more people will invest in bitcoin.
Casinos is the place where the gamblers get together and gamble and all the money they have in their pockets which is paper money or bitcoin will be used for gambling anywhere in casinos or any other place for gambling. Like my country there is no casino because gambling is illegal and the security will put you in jail if they found you gambling. Therefore all the gamblers gamble in a secret place.