Probably the one that differs the most from online casinos is the ability to socialize; therefore, people don't come only to play but also to come with friends, meet other people, watch others play, etc. Also, many casinos are interconnected with nice hotels, shows, escort services, and many more lol.
If about the game itself, I think the psychological thing is the same as online games, mainly about adrenaline rush and dopamine boost.