Don't you think that a woman who has casual with a lot of men, say over five, has low self esteem?

and is selling herself short? Most men are not desirable, unless you live in a major metropolitan city like New York. Most men are even below average looking, I would say. So, why would a woman have casual with a man who isn't even extraordinarily good looking. What's the point? I could understand if there was an established relationship, but in terms of casual if a man is not extremely handsome, the whole prospect of a fling wouldn't appeal to me. What do you think?