Bras do serve a purpose as an item of clothing to mostly hide the nipple but enhance or minimize the look of the breast on the whole. The bra is a amazingly high tech object from the sewing, the hardware and the latest innovations in fabric. Bras change as the technology changes and with the culture.
Bras are far more cultural than functional. Bras are selected so that a women can feel good about seeing themselves in the mirror. Obviously every woman has a different impression of how they look. Beauty is in the eye of the beholder.
Not a woman, been around a few.