Your fandom lets you develop business sense, a sense of customer service, and entrepreneurship. If you think I'm done talking about the professional advantages of your hobbies, it won't surprise you that I'm not done yet.
Fandom teaches you courage.
That may sound strange to some people – until you think about what fandom actually involves.
Doing things in public? Running a convention? Taking fanart commissions? Running a website. Everyone is watching you. Every mistake you make is obvious. Every error will be on the internet or YouTube or twitter. You've got a lot of courage.
Taking financial risks? That convention could fail and leave you and others holding the bag. Is that website paying off? Are you making enough on commissions? Are you going to that con in the hope of hooking up with some pros and blowing huge wad of cash? You've got a lot of courage.
Running your own business? That art table you've been doing at conventions has shown a lot of courage. Or maybe your cosplay consulting. Or maybe that book you self published. You've got a lot of courage.
Impressive, aren't you? You've been doing all sorts of efforts and engaging in all sorts of endeavors that took a lot of courage and you didn't appreciate it. Next time you have to take a risk – say, starting that new job or launching your own business, maybe you'll appreciate the courage you have.
(Or, possibly, the above just made you realize how many risks you've been taking, and now you're a quivering pile of jelly. But I hope instead you'll appreciate the courage you've shown.)