I never understood why you should not care for beauty just because it will pass. Yes, it will. So will life. Does that make living it while it lasts unimportant?
Honestly, I've tried to date girls that I liked as a person but was not attracted to. It didn't work. I still wanted those women I found sexually attractive and felt bad about being with someone who didn't make me feel that "spark". I simply can't deceive myself into thinking that I am content when in fact I am not, and it's only the beautiful (or at least somewhat pretty) women that make me feel any kind of excitement or desire. And without that, a relationship is simply dull and lacks the very essence of it which is excitement and attraction for your partner.