Maybe it's by design, but Show HN posts seem to just get completely buried, whereas posting stuff directly is more successful

I've spoke to other people who've had the same experience, maybe just a coincidence but could be why people avoid it?

Show hn was overrun by ai slop for a while so I and presumably many others filtered it out of our feeds. That would have resulted in show hn getting much less interaction and potentially led to people not wanting to use the feature.