Why is this song actually here?

Last Friday, Pitchfork posted an interview with Kim Deal, of Pixies and Breeders fame. Here she is, musing on artistic necessity in the age of ProTools:

I'm not the quickest, most prolific writer either. I would never pretend to be. I don't think prolific-ness is equal to quality at all. I would rather have one song that people actually like than 15 songs that they can barely stand. But that's just me.

Another thing is, I think it's kind of ballsy to sit there and think that [people want to listen] if it wasn't special and we weren't trying to do something we would want to listen to. Why is this song actually here? Why is this song taking up two-and-a-half minutes of my life? Is it just because somebody doesn't have tape anymore and so the amount of recording space is unlimited? That's why I'm sitting here listening to this, because nothing stopped you from doing it, but there's not really a reason to do it? I don't know. If that was me, and I was listening to me, I would get mad, like, "Why are you fucking doing this?" It doesn't have to be great, but it seems like at least there should be kind of a reason. And it's hard to come up with a fucking good reason to write something, I think.