You really never know what mathematics discoveries can do. Number theory was an useless brach of mathematics, considered an useless endeavor of theoretical mathematics and basically a hobby. Until modern computation and the RSA algorithm gave number theory an use, and without it, the internet as we know it, couldn’t exist.
I used to visit an specialized private tracker that went offline, deli.sh, it’s had only food content, like video courses and a lot of books. Everything had at least a couple of seeders, so even that ultra rare French language pastry book was available to download. My girlfriend, now wife, was on cooking academy and I downloaded a lot of books and courses for her that would be unavailable anywhere else on the internet. I don’t think you can really have that kind of collection on a public tracker.