Piracy: ꜱᴀɪʟ ᴛʜᴇ ʜɪɢʜ ꜱᴇᴀꜱ

The monetary barrier to usenet is probably why torrent trackers would be more popular, and thus more likely to be blocked by national regulators. As to why you're far more likely to get an ISP letter for torrenting than for using usenet, while the bittorrent protocol means than if you download a release you're also seeding it to others, paying usenet providers for access to their cached releases means that you're only downloading releases from them, and not uploading anything.

Comparing the cost of a VPN to Real-Debrid + a Usenet Indexer + A Usenet Provider depends on which services you choose, but in the case of ProtonVPN , NZBGeek, and Frugal Usenet it comes to $72 vs $84 a year, with the latter being more if you want to add a backup usenet block plan from a different node (block plans have a one-time upfront cost and last until you use up the plan's download capacity). If you forgo the additional block plan and NZBGeek, instead using a combination of the free tiers from indexers including Tabula Rasa, NZB Finder, Miatrix, and DrunkenSlug (most allowing for 5 free downloads a day), Real-Debrid + Frugal Usenet is the same as ProtonVPN at $72 a year.

it's not that they sniff traffic for torrents because that's as you said encrypted it's that bad actors can join public trackers and gather all the ips and send them off to your isp if your on private trackers that you trust you don't need a VPN