I actually had a use case that would have made sense to use this, in theory, but the implementation left a lot to be desired. The tracker Amazon ran was really trigger happy to ban peers (I'm sure it saw tons of bad actors, but still, it made testing really painful especially if you were churning infohashes as you tested new objects). And the seed was somehow painfully slow. Never once did any of my test scenarios see faster downloads than just downloading from S3.

Maybe if I got some critical mass of users seeding, but since I couldn't get stats out of the tracker, I had no way to encourage users with gold stars or whatever.

And, on top of all of this, since you couldn't create a multiple-file torrent with this, you had to really work around silly limitations.