I've never liked them outside of the niches the private trackers I had access to were about.
I've had one that sucked for anything other than music (and even the music was annoying because the uploaders had boners for FLAC and this was back when file size still mattered and FLACs are fucking huge and don't sound different enough to warrant the file size), one that only hosted textbooks for college courses, and another that was strictly niche as fuck films that nobody has ever even really heard of.
It's good to filter out bad actors uploading viruses, but it also limits how much stuff is there period.