The title of your post asks “What is your view of website page rank, does it really serve any purpose?”
First, let me say that there is no such thing as “website page rank”. Google does not rank websites, they rank individual web pages.
Pagerank is an important signal used in Google’s algorithm to weight the value of anchor text. Anchortext is one of the 4 primary signal groups and as such is a very important metric. Pagerank is just a weighting factor, not a relevancy factor, so its impact occurs primarily through how it weighs the anchor text, signal group.
The 4 most important metrics for SEO besides the SERP ranking are the 4 primary signal group search operators: