Gambling is for fun. Higher bets can get you higher wins but can also make you go bankrupt. You cannot become rich with gambling, if you want to become rich work hard and focus on your career.
Yes, but if you have big luck, you can rich from gambling. There are just a few people, e.g a guy on primedice, he made his 2 BTC to 300 BTC (not hufflepuff), and another person who profited 500 BTC from Bitdice.
I'm very agreed with your bolded opinion.