man, the internet archive really did not need more on its plate right now
as we all know, if you care about something, save it. if it gets taken down, you still have it. great! but what about getting that thing to other people? a lot of people here mention that they care a lot about the preservation. but if you're the only person in the world who still has a copy of something, it's basically still lost media to everyone else.
torrent trackers make this content not only available, but incentivize people to keep it up. you can see the number of seeders on something, which shows how many other people are also sharing it. having additional seeders allows people to download that data faster, but is a built-in system for redundancy - if one person loses that data, the other 49 seeders are still there.
while not outright required, i'm moreso talking about private torrent trackers here. you've probably heard of public ones like thepiratebay (lol) and while those do still work, because they don't track stats on individual users, people tend to just visit to pick something up and then immediately leave once they have it. semi-private and private trackers not only have rules about holding the door open for a certain amount of time, but they're often organized better, have a more focused scope, and a greater sense of community.