I stopped caring about pr a long time ago if google updated pr everyday or if they decided to stop updating it all together I wouldn't care
agree with Rena PR is worth, wisely to understand how PR relate to your site maybe very helpful for SEO example : if your site always keep PR = 0 , it may tell your site has poor traffic most of time. what if your site have very high PR but no traffic at all, it may tell you that your site may be poor of contents and not attracting people to come back but may only have a lots of backlinks.
PR has nothing to do with traffic, traffic is what you get from SE and other sources whereas PR use to a small factor responsible for ranking.