Totally de-centralised - your post on your local NNTP server, and it gets replicated across the NNTP mesh to all the other servers.
Built in threading... Actually HN is very similar to how a fairly busy newsgroup would look back in the day.
Weaknesses:
Posts used to take hours (sometimes days) to replicate across the whole mesh. Not so much nowadays tho.
Text only; no native support for rich media or Unicode (although some might see that as a Strength)
https://groups.google.com/forum/feed/comp.misc/topics/rss.xm...
I'm on the hunt for a good dedicated Windows NNTP reader, failing that I might have a go at writing my own (that supports text posts only - none of that dodgy binaries rubbish!).
A good newsreader needs to be able to thread and block and filter and preview binaries. Few apps ever did this well, and many that did have since become obsolete (Pan2, Unison, etc).
With the rise of Windows and the decline of Usenet, the demand for newsreaders faded fast, leaving few or no supported freeware newsreaders alive today. Even commercial newsreader apps are increasingly rare.