there is luck involved into it anyway, even if you can compare it to poker, the risk of losing is always there, especially if there are others skilled traders(same case with poker, with many reg you can't earn shit), and at that point if you are against people with the same skill as your, it beocme a game of luck...
Indeed, if you want to earn more, you would have to rely more on sheer luck, but there is some level of positive outcome (like negative house edge) that lets you earn a little without risk at all (since trading is
not a zero sum game). To avoid further confusion, I don't take into account systemic risk here such as a risk of an exchange going bust, blockchain compromise, or things like that...