I know of them from before/outside HN; I haven't noticed them being especially common here. I think of it as a petri dish of investing clickbait.
The merit, if any, is that it incentivizes writing on any given public company, but most of it is worthless.
The other thing, that wouldn't be on HN, is they link to earnings call transcripts. I don't know if there is some other easy way to obtain them, but it is the channel I'm aware of and seems useful.