There is nothing wrong with selling your creations, no matter what the profession is. And people WANT to buy other's creations. Thats the beauty of it. Someone may love Art (Paintings, drawings, photos, etc) but not have the time / inspiration / desire to create it for themselves, so they pay someone else to have the all that for them.
If this person "loves" their job, then its even better because they are thinking "this is awesome, I can't believe someone pays me to do this. So I don't need a job doing something else to pay for my hobbies!"
Its the same reason I don't design/engineer/build my own cars... someone else loves that more than me, and is therefore much better at it than me, and I appreciate their expertise and compensate them accordingly.
This young "whippersnapper" that is going off about how they live in their parents house for free will certainly change their tune once their parents push them out of the nest (as good parents should), or once they realize they are 30 and still not able to support themselves, let alone a family of their own.
In the end, do whatever you love (within legal bounds of course) and if someone wants to pay you to do it... you're in the clear.
I sell photo prints, and I'm just an amateur photographer with a grasp of photoshop. I couldn't make a living JUST doing that since I don't spend enough time doing it. But I think it's still pretty cool to get paid for a hobby (but I really want to be doing this with art instead of photos... someday)
Current Artist Level - Straight up begginer