If I was rich I would still gamble without any doubts, the fact is that gambling is just so enjoying and you can do it for many hours and it stays fun.
If you are rich you also have nothing to lose, the only thing you should do is not put too much money into it.
it doesn't stay fun forever especially if you play the game over and over for many hours, that turn into a boring activity so fast.
also in gambling you can never always win so as they say, you will lose in long term. in other words if you continue gambling for hours, you will be facing that losing streak and continue down the hill. and that is no more fun.