I'm a torrenter with the sonarr radar lidarr prowlarr *arr setups.

I've dabbled with Usenet and here's my understanding.

With torrents you're all sharing something live, if you want ubuntu.iso and I have ubuntu.iso you can get it from me and many others who seed this file. A torrent tracker (or the dht) helps put us in touch so you know where the file is.

With Usenet it's more like I dead drop this file, zipped and encrypted(?) onto a Usenet news server. All the Usenet providers mirror each other or something like that, so if you're on a diff provider than me that same file should still be available. Then I tell an indexer, like dognzb or nzbgeek that this file is in fact ubuntu.iso and not garbage data. When you want ubuntu.iso you ask the indexer, indexer gives you a link and you get the file.

Beyond this, I don't know about how much safer it is, but my immediate guess is that since you're not seeding there's less risk.

Now if you're really snobby like me, you'll quickly realize that the release groups you're used to aren't as well represented. I've often landed in situations where episode 7 of 20 is missing on Usenet...

As a snob, I've decided private trackers are probably the best place to be to keep my quality expectations satisfied.

Hope this helps.