There are a lot of women who are win beauty contests or are pretty enough to do so. Very few of them have public careers, whether in entertainment or otherwise. Marilyn Monroe and Dolly Parton have said sharp things. Even if she got an advantage from her looks (and that's rather an ambiguous thing, especially if she isn't in entertainment), she's at least well above average on social skills and ambition.
None of this means she'd necessarily be a good choice for president, but I don't think she's a non-entity in this story.
Here's an interesting angle-- McCain likes her, not just because she's a beauty queen (though he seems to have a taste for them) but also because she's a fellow reform politician.