This will almost certainly be used by people to sanity check their HN submissions before actually submitting, very similar to having AI review your branch before submitting a PR.
Or like Nathan Fielder's The Rehearsal show on HBO Max. Also, the show's subreddit has a companion subreddit for posting to before you post to the real one.
A friend of mine was speculating about the same thing. I'm totally happy with it just existing as a toy, but if it serves some useful purpose, even better!
Here is what it has to say about itself: https://news.ysimulator.run/item/113