I'm an independent contractor and I tried for a few years to apply to the announcements on HN.

It was generally a bad experience (no reply or bad interview process).

BUT... a few years ago I randomly applied for a very niche job I would have liked and spent 1 year doing some pretty amazing stuff. The company got a nice exit too (alas, I had no stock).

So, I don't think HN ads are pointless, but they are pretty random just like any other recruiting platform, etc.

Oddly, I found the next job on LinkedIn at a big corporation! Lower pay, of course, but interesting (to me) domain.