Is Physical Attraction Important?

I finally saw some additional photos of the online girl and discovered that her looks aren't what I originally expected. I don't want to seem shallow, but shouldn't there be at least some physical attraction if I am to progress further? Or are all women the same and that the only determining factor for their looks is their skill with makeup? Part of me tells me to continue trying to date her in order to gain experience and confidence with women. But the other part of me tells me not to hurt her anymore than I already have. I stood her up once and argued with her thrice. I don't think a future inevitable breakup will do her any good. I'm not saying that I'll abandon all future contact with her. I'll continue having her as a good friend, it's just that the feeling might not be there anymore.