Does it really help to get better PR and traffic by getting backlinks from any site, which may not necessarily be your niche site also ?
All links are important, but you will gain better ranking positions if you only link to related niches. Good luck
All links are important and it is a myth that links from "bad" websites will affect your PR. Thematic one-way link from authority sites are the best. My digital online store is not getting any thematic links because competitors will not be so generous but it is ranked among the top 5 on page 1 of G for the keyword of "digital products" which is highly competitive. Its 2,500 "1st priority" internal links are giving its good position. The 2,500 webpages don't have the normal "Home" links (first links) to the homepage. I replaced it with "Digital Products".
It is a fact that links from "bad" sites will lower your pr and your serp. Links outside your niche will hurt you too, if you have hundreds of them.