Answer: Yes, yes yes!
IMO it is very worth it. Even if she is ugly, at least you can argue she has lots of friends that are hot or it can be good for social proof.
But leaving that aside, I don't think it even matters, I think that yes it is worth it. It's a friend!!!! CMON, don't you guys enjoy social contact? Sometimes you don't feel like talking to ppl, but most of the times talking to ppl is just cool and it beats being alone lots of times. Especially since it's a girl and girls can be super fun, even more if you're fun yourself. DJs sure bring the best out of people. If you don't have enough human contact you may turn out psychotic. Have as many friends as you can, talk to people you don't know well at all, don't avoid social contact most of the times.
I'm speaking generally, but every situation is different, sometimes you rather be alone... I sometimes want to be alone but often is because I'm pissed off at something, if I'm feeling good I just want to go out with people!
And why be worried that she's gonna ruin your life or something like that?? "Don't be friends with girls that are crazy", do I understand this? If you're a man why be worried that a girl will bring you down? You're capable of being so emotionally strong that words can't hurt you at all, and she's a girl.... Put her in her place, if she's messing around you don't have to be annoyed, play along or tell her to stop, something like that, you can handle her can you not? Why worry?