Replace "casino" with office and "game" with computer and this starts to sound a lot like a cynical take on many people's jobs.
I think part of it is the allure that the money has been "won" instead of "earned". You are "beating the system", or "sticking it to the Man"... I can't think of why else you'd subject yourself to this un-ergonomic work environment.
For people who just want to earn a living and go home it doesn't sound too bad.
But the major downside is the lack of creation. I enjoy construction as well as software development for the same reason. At the end of the day (or year perhaps...) you can see something, that did not exist before, that you have created. That just feels really good. In gaming, you can make plenty of money but you aren't really creating anything and so it ends up feeling quite empty - especially when variance is doing its thing.
Second hand smokers need not apply, first hand is what it takes to succeed. He also gets the ability to walk away whenever he needs a break, for as long as he wants. He has a captive audience who has to listen to his latest feelings on Obama or Big Foot. And a surprisingly amount of random encounters that result in sex.
He used to drive taxi, then Uber for about the same take home. But what really makes him stay with video poker is the free gifts from the Casio (swag mostly), and the ~ 100 senior citizen ladies he romantically encounters each year.
FTFY.
In some ways its better, choose your own hours. In my country, tax free earnings. Where do I sign up?