The purpose of a clothes model is to sell clothes.
Better upholstered models attract attention away from the clothes to their bodies.
Models need to be reasonably attractive, or people (most customers are women) will focus on their zits and such, but one should not assume that models are the epitome of beauty.
Women will never fail to notice that a handbag and shoes do not match. They will notice the difference between a French manicure and other types of manicure.