Gambling has only two options, win or lose, trading has similar two options (sell with or without profit) but also allow holding. I would say that gambling is 50/50 chance to lose, when trading its +1/3 chance to lose money. And it is obvious that it is easier to start gambling, than to start trading. Even registering and first steps in gambling are easier than in on any trading platform, if you are totally new and start with fiat.