What? I've never seen the movie but this doesn't make sense.

Her appeal is strictly based on "beauty" and occasional repartee.

That's exactly what men find most attractive they don't care about anything else but visuals. They may parrot 'conservative values' but they are following and liking the IG 304s.

Are we supposed to believe this woman is attractive?

Yes. Yes, she is a beauty icon because she is thin. You can never be too skinny or too rich. That is why twiggy and Kate moss were icons. That is why Kate middleton got William back after he dumped her - she became, and has stayed ana/anorexic. Thin is beautiful. All the top women in Mayfair are super thin.

She gives mixed signals and blows hot and cold. That is recorded as one of the best methods of seduction

Ok, if the male love interest is a THOt 304, that is pretty gross and she will never be happy with him. He is not a provider, he is a parasite.
They will end up both going back to being hoes even if they stay together.