It's a complete waste of money and time but base on my observation when I visited a casino, for the rich people, that is how they kill time in my honest opinion.
They enjoyed that way although they have to spend, but there are different type of gamblers, those who are into full entertainment and those who are into real gambling where they have their main goal which is to win. In addition, we have different games as well, so anyone can enjoy or gamble on its own preference.
They must have a lot of money that their only past time is gambling. They must have done all the things that life can offer. So for me gambling is really a waste but for them it is the opposite.
Some have a lot to waste but most gamblers are hoping to win.
Me personally is enjoying gambling but I don't think it's a waste of time as I also have a purpose, I can gamble anytime at my preferred time
and spend only what I can afford to lose, that's what I learn and become with years of experience as a gambler.