There are many reasons in gambling, for example just for fun, eliminating the burden of the mind even for profit. If you think just for profit means you are wrong thinking. Because gambling is a lot of harm than good.
I can understand that gambling might be a hobby for someone but aren't you afraid of loss? I'm able to control myself but what about other people? Not everyone will stop at the right moment before the lose everything. I don't think you can earn much by gambling without having a lot of luck.