Girls, why would you want to be friends with an ex boyfriend if you knew he liked you?

My ex girlfriend and I are currently friends. In the 20 months since we broke up, our relationship has gone up and down a ton; talking to not talking, to talking, to friends, to not friends, and now friends again. One of the products of dealing with high schoolers I guess :P

Anyway, last week I told my ex girlfriend that I still loved her despite all this time that has passed since we broke up and despite all our ups and downs. She told me that she didn't want a relationship with anybody at the moment since she doesn't want to devote herself to somebody and then move away for college (We're both seniors right now). She also said that she had goals in her life that didn't involve relationships and she has a pretty negative view of relationships anyways at the moment (see my previous question for details).

I then asked her if she still wanted to be friends, and she said yes. I mentioned that it was unusual for people to want to be friends with their ex'es in general, let alone one that still likes them. I asked her why she still wanted to be friends, and she said "I don't know".

Obviously I'm not complaining about this, but I do find it odd. I know if she were the one that liked me and I were the one that didn't want a relationship, I would feel too awkward to hang out with her and be her friend. Is that just me?

Girls, what reasons would you have for doing this?