If a casino owner use his casino to bet or whether he bet outside his casino is the same thing. What matters is self control because the fear of not betting with his casino is not to over stake but he can also over stake in another casino so what matters is self control and not where an owner plays.
We should also remember that a casino owner is also human with feelings and emotions and so he is liable to make mistakes that gamblers do not necessarily in his casino. So he is at liberty of choice if he so chooses to bet, he is not barred from gambling in his casino excepted he may be tempted not to be professional and responsible to his betting.
But in my opinion it is very unethical for casino owner to play in his own casino because it will be question of what his purpose is in playing in his casino because he can play in other casinos while trying to see how the development and services of other casinos which are also his business competitors.
If we are talking about making profit then he doesn't need to play in the casino he owns because just by running the casino he can make quite lot of profit.
Meanwhile, for reasons of having fun, it is also impossible because when gambling in place that he built, it is the same as playing with system that he himself, has created Is this worth it?
Moreover, winning or losing will not affect anything, what is left is less good view from all his customers if such an incident were discovered.
But why would something like that be done because he has team, he has employees who manage each game and of course everything is managed by the casino employees, not the owner.