Page rank is a bit idiotic to use when selling banners, it doesn't reflect how many users you got, nor the quality of the site.
0 PR certainly is better than nothing: when I first start my blog http://www.consultingcase101.com, it has no PR, after 3 months, PR is 0, the lowest one on PR scale.
I agree with the first half of your statement, PR doesn't reflect number of users or traffic, higher PR does indicates higher quality of the site, meaning higher authority on the subject/topic for blogs.
Higher PR can help, in an indirect way, with traffic and therfore with revenue (if that's the purpose of your site). Much more important, in my opinion, is the PR of the sites that are backlinking to you.
It's not idiotic use it when selling banners. A seller should use every detail possible to pitch his site in order to make the most money. If anyone is at fault for over-rating PR, it's the buyers. But, in my experience, even a fully informed buyer is just waiting for an excuse to buy. Piling on data about PR and links and visitors all serves to push the buyer toward their inevitable conclusion. I had a web design client a while back who I repeatedly told his project was an utter waste of money and that he should stop spending on it. Ten years and $100,000+ later, he's still spending and still not turning a profit. In fact, he pretty much called me a bastard for not continuing to cheerlead. My point? The capacity of buyers to want to be convinced to give up their money is astonishing. And it would be remiss for any seller to not help them along that path.
no major update for sure, but minor update from time to time, several people have reported minor update to their sites on DP