Is that a direct quote? I got a very different impression from the article. It seems they are looking more at a societal level. The women can still be exchanging sex for resources, even if they are the ones desiring sex. For example, it's common for a woman to flirt to have a man buy her a drink, pay for the uber, etc. So while they ultimately want sex, they know they can get sex plus some other resources.

Obviously this can even be the inverse in individual interactions, as their chart eludes to for what lowers or raises the price (age, attractiveness, etc). Just as their statement about there being no value to male sexual favors is only true at the societal level (maybe not even then) and not the more granular one.