Apologies if this is a basic question, but I am curious to know what I am missing out on by not having access to private torrents? I have been able to find everything I wanted using public ones.
Well, imagine private trackers being like subreddits or magazines in the Fediverse. There are private torrent communities that only share TTRPG books, files for FVX/Motion Graphics, Art/Photography books, Magazines from a certain era, STL files for 3D printing, etc. And all of these trackers have very strict filters for both posters and visitors so the quality of the content is top-notch.
In these trackers, there is stuff that you won't find elsewhere, period. Talking from experience... Good luck finding scans of Spanish tech/video game magazines from the 90s/00s, or copyrighted stuff like precise 3D models of Nintendo Switch's Joycon shells, out in the common web.
My problem has been that I don't have any idea where to begin to look for these or get access.
I use a VPN, I have subscriptions to Usenet hosts and nzb trackers. I seed aggressively, especially stuff with low seeds or that I generally just think should be shared. But apparently not in the scene enough or tried hard enough to figure out a place that even has stuff I want besides the public ones.