Beauty is only skin deep, and celebrity is pretty much confined to the epidermis as well. Celebrities are books that, for the most part, want to be judged by their covers—particularly a certain kind of celebrity.
We've reached a time when a woman who gets the right breaks (including being born into celebrity) can be kind of a big deal without actually doing much of anything. Celebutantes, models of the moment, athletes with more sex appeal than skills, actresses who can't quite find that legitimacy-conferring role—while these might all seem to be types of second-class celebrity, it's not necessarily so.
If you're hot enough, you can be just as famous as the talented (or more successful) ones.