Don't get too serious about earning money in gambling. The risk is higher than investing just playing as usual while entertaining yourself.
Right, gambling should only for fun, it is not best way to make money because it is purely luck and because of the house edges the longer you play the bigger chance of you losing. I think it is better to do investments or trading instead wherein you can use a strategy to win.
Gambling is a game of 50:50 chance invariably a game of luck there has never been a strategy that can have an edge over the bookies although some player wins big but are very rare that is why its always advisable to gamble with the amount of money you can afford to lose however a better alternative to it is trading as you rightly said which I believed is a very sure way of making money with a lesser risk compared to gambling but requires some learning process before becoming a successful trader.