Great sharing by the original thread owner.
First of all we need to define the term "PBN" . This is highly subjective because PBN can range from a low quality one (whereby it gets spamy and serve all niches, in the case of LINK building providers) or a high quality PBN whereby is done up right, with content pages, contact forms, emails, serves almost identical like a legit website.
In the case of high quality PBN, if done right, it could also be considered as a "Guest Post". Because is LEGIT. I mean think about it, is just like another website own by others.
in most businesses, where sales and traffic matters, unless you are a figure of authority and providing GOOD CONTENT for free with "the intention of just sharing to the world your knowledge" (yeah right, lets not kid ourselves ?) , then backlinks are definitely a go-to as it serves a major driving force of ranking.
Whats most important is, how you are going to build such that it seemed NATURAL in the eyes of human, as well as google algorithm.
So the conclusion is, there is actually no right and wrong. SEO is an on going process, algorithm changes everytime, so what matters is always trying out what works what doesnt, and share around. That way we ourselves can grow as a community and prosper together. Cheers!