Why does "nobody much care about who sees the face of a Martha", but there is so much concern about the clothes of the Handmaid?

The Marthas are household servants. They have no tasks other than to clean, cook, and take care of the Commanders' homes. Thus, their appearance is unimportant.... the handmaids, however, dress for the Commanders' enjoyment.... they are also the perspective birth mothers for the Commanders' children.