I agree with all of your reasons for visiting HN. I've mentioned this before on another thread, but the guideline that posts should be "anything that gratifies one's intellectual curiosity"[1] tends to produce a lot of content that I find interesting, and I'm sure there are many more people like us here.
One thing that I will add is that I wish that people posted more non-programming jobs in the monthly Who's Hiring. Even if you just posted the approximate job title it'd be better than omitting it entirely. Every month I control+F>"mechanincal engineer", and there are almost never more than one or two posts, despite the fact that I see some of the same companies posting these positions on different job boards.