Hmm...I agree with almost all of these, except for a couple. dA has definitely made me a better artist and revived and nutured my passion for drawing. Plus, I love looking at other people's art too and seeing the interests we share. The dA community is so welcoming and nice! But I agree with you; thanks to dA, art has definitely become an important hobby of mine, but I wouldn't want to become a professional artist and MAJOR in it or anything.
dA can definitely help with that too. There's just so many resources and so much support on this site; it's the perfect place to go whether you're an amateur like me or an art major in college. That's what I love about dA!
I think a lot of people join to enjoy art. I personnaly include myself in the "Kids that are not so good(learning) but may become good"... if I put some extra work I might! But there are still a lot of good artists on DA!