The cost of maintaining and acquiring it will indeed be higher than the cost of filling that casino with competent employees that will serve the people well, and you as the employer will still have some left-over money, not to mention how those robots might malfunction at times due to a lack of servicing or a system breakdown.
To me, it's completely insane to leave an entire physical casino to be handled and controlled by robots; if they must be present, there are areas where few of them can be invested, and they will work perfectly in that area with the assistance of human actors.
I agree with you, maybe there will be times when something unwanted happens like what you said with a robot that malfunctions and it can cause losses besides the repair costs may tend to be high so you have to spend a lot of money to fix a broken robot. The same rights as humans where if a casino worker makes a mistake it will definitely cause problems and inconvenience to customers who visit, only I don't think there is a cost that must be incurred to fix it because in general workers who have made mistakes will definitely apologize and with full patience they will be more careful to work again in the future. Considering that robots are also created by humans so no matter how smart the robot is depending on who makes it, they will not be reliable in all things I am sure of this, agree with what you said it sounds crazy if a physical casino is completely controlled by robots, there might be interactions that make customers uncomfortable.