It all comes down to perspective. If you are selling links from your site based on PR, then it would be very important. However, if you are not in the business of selling links, then Google PR shouldn’t matter.
The bottom line for any business online is traffic and conversions. Nothing else really matters. A high PR is not necessary for a site to get huge amounts of traffic. In fact, a high PR doesn’t even guarantee a placement over lower PR sites.
In the last couple of years, Google has made it more difficult for sites to attain a high PR. I think it was a sensible decision because so many bogus websites were springing up purely for the sake of selling text links. And, selling text links for the purpose of manipulating the SERPs is against Google’s policy.
Although I am not completely innocent from the practice of selling or buying links, I’ve never personally created a site solely for the purpose of selling links. I believe that every site that is built should serve a greater purpose. A site should work to solve a problem (product or service) or help the public answer questions (information).