Personally I use public trackers the most and only recently private trackers for stuff in my native language.
I did setup i2p a few days ago and currently have only downloaded around ~1GB. Most of my bandwith (143 GB in / 135.5 GB out) has come from just having it in the background 24/7.
The advantages of usenet don't really apply to me (longer retention, faster speeds, no vpn)
Streaming i find useful for checking if something is worth downloading
How the hell are there more Private Tracker users than DDL users
usenet IS direct downloads. Unless DDL you mean like mega, mediafire, dropbox, gdrive, pxieldrain, rapidgator, debrid etc etc.