While ‘the paywall for access’ argument can be made for usenet indexers (which just index NZB files, not the releases themselves, with most still allowing up to 5 downloads a day via free membership tiers), in contrast to torrenting, usenet providers cache newsgroup binaries (the actual releases) on the servers of their respective usenet backbone. Because of that, releases that might run out of active seeders on public or even private torrent trackers after a few years are sometimes available for significantly longer on usenet.
Edit: While it’s not an excuse for the usenet indexers, rather the providers, usenet newsgroup binaries are downloaded directly from the servers of providers, and are thus not P2P like bittorrent is.