The article also mentioned wearing sexualized clothing like really high heels as a direct reaction to a male compliment. Responding to personal male compliments on dress is saying, "I am here to please you". There is eye contact based on interest and respect in a business sense, and there is eye contact that has a swoony manner where your pupils get larger, tip your head, be too close, and you hang on their every word suggesting an infatuation. They said the flirting is subtle and conveyed in the nuance of the normal type of interactions. The article is saying to "flirt between the lines" type of thing.
I think what it does is boost the ego. It gives the illusion that women are attracted sexually to the men even if they won't cross the lines for professional reasons. The ego is still boosted by the undercurrent of possibility. The problem is that the ego is equally offended when that undercurrent possibility is not offered. A woman can make male enemies based on that alone.