PR is fairly worthless, but as you say it does help with exchanging or selling links since there are so many people out there that don’t consider the more important metrics (traffic, rankings, etc.)
That said, our PR is up for our sub-pages which is what we have been working on getting links for over the past several months, so at least it is a measure of some sort of success, but we knew that already since our rankings were improving.
Not that it needs to be said again, but…chasing PR alone is a mistake