Unfortunately today people judge others by their looks rather than whats in their attitudes and heads. Today you can be the nicest person on Earth and be butt ugly and no one will care about you. You can be a complete snob and bully but look like a fashionista and people will be all over you no matter how manipulative you are. The world has changed for the worse buddy and it's never gonna get better.
Depends on how you look at it. You can either analyze it too much and to some point be right that it is vanity OR you can see it as "doing art on your face" and someone being presentable and proper because then again you can't really see how beautiful someone's personality is at first sight but then again lots of beautiful people get overlooked because of it. Potato, Po-tato.
When you look good, you feel good. Knowing that I spent even a little time to get ready and that I look good makes me feel good. Do I care about how others will think I look? No. As long as I know I look good that's all that matters. Confidence is the key.