Sure, learning a complex competitive game in their youth shapes your logical thinking, handling pressure, and learning how to handle people in a competitive 1v1 situation (think sales or salary negotiations).

I know a lot of people which were playing, and than moved on and changed their career to either poker player or studying computer science, or both.

Well, it contributes greatly to the arts? Sooooo much artwork on soooo many cards fueling soooo many payments to soooo many artists. The fact that WOTC has been able to continually innovate on the game and maintain interest has resulted in artists being given continuous opportunities to get their work seen and handled by hundreds of thousands of people.

I made a lot of connections when I was younger with people a few years older than me that really helped lift me up. I gained a lot of logical skills from needing to read about how cards interacted and apply that to judging small tournaments. I'm guessing a lot of people used it as a tool to be social when they didn't otherwise know how.

That all by itself seems worthwhile to me.

Sometimes brining joy to people is enough.

Good question, what's your contribution to humanity?