I asked Sa this question: Why should Ladies use Eye Liner?
After thinking for a while her reply was, remember when we were younger we used to outline our art pieces with a black outline pencil? That resulted in our drawing becoming more striking and attractive.
A face is like a canvas which needs to be filled with a little bit of colour to brighten and highlight our features. A young lady usually looks more attractive with make up than without! With the exception when she over does it :)