"Why is erotic admiration valuable? Because being on the receiving end of erotic admiration is beneficial. Ronald E. Riggio has written about the benefits of being the recipient of sexual interest. In "How Men Increase Women's Sexual Attractiveness" he summarizes a study that shows that women who are being interacted with in ways that convey that men find them attractive display more poise and warmth. Perhaps this "Pygmalion Effect" also works on men who receive erotic admiration.
A second benefit of erotic admiration is that it allows men and women to be friends without trying to be asexual. Erotic admiration prevents inter-gender friendships from morphing into romantic entanglements without the friends pretending to be genderless."
See entire article @ Psychology Today