The comments on the Ask HN, Show HN are usually very informative, and have helped me a lot in my own side projects and entrepreneurial pursuits.
The comments on stories (for me) act as a curation tool, and based on what I read, I actually decide to either read the posted story, or pass on it.
W.r.t. stories posted, 9 /10 times, the comments are more insightful and offer unbiased commentary that the original stories -- many of which (on the internets, not HN) are click-baity / shock'n'awe type posts -- often lack.