In terms of turning passions to profit, it is way harder to earn from a hobby that was self taught than to earn from other skills or jobs or as an employee under a boss.
I think those who are crazy enough to turn their hobbies into a source of income and attain wealth unimaginable in the end know how hard it is to be patient, consistent and persistent despite criticisms and many setbacks, to get to where they are today as successful. Whereas those who get employed and have to work to earn a salary or earn from a skill that was learned somehow, don't encounter this much difficulty that may lead to financial freedom and breakthrough.
What do you think?
It can sometimes be a bad idea to mix your hobbies and try to make an income out of them, because it can eventually suck out all the energy or the original reason that attracted you to it in the first place. It's better to just let it progress naturally and do not try to push it too hard. If you have been doing something for a long time and see that there is demand for your product or service, then by all means make a few extra bucks - but do it because you enjoyed the process rather than approaching it with a complete business mindset. You may be one of the few people who conquers a niche and successfully launch something big out of their hobby, however you may just want to keep it as something you enjoy in your free time.