I think that even though you make a good point about attractiveness being correlated with intelligence, having a bias towards being attractive is equally as bad as a bias towards rich people. Sure, rich people are typically smarter, because they get better education. But ideally we should be choosing employees based on the abilities, rather than things that could be indicative of their abilities.
And I don't think employers hire attractive women because they are more intelligent. They hire them because they are attractive, which is the problem the article points out.