Good stuff to think about! I learned much from this article!
On the other hand, there is an even deeper, psychological sense that you did not mention yet: The effort of being “beautiful” shows, that you are trying to be part of a certain environment, a certain society, that you are trying to fulfil a certain role model, and that creates a value of itself. Moreover: that´s why prussian soldiers were forced to take special care of themselves and their uniform — and why people even in concentration camps were able to generate a form of strenght out of their daily, cultural rituals: washing themselves, praying, reciting literature, painting. The sense of beauty is forming a culture as well as a cultural consience — and standing outside, the denying and neglecting of traditional beauty, is a confrontation — hundred years later called punk.