You're wrong because because even if two people or ten people download your torrent uploading 10GB is enough. Quick explanation:
Let's say you have three users download your file and the file is split inside the torrent into 3 parts (simplification, real torrents have a LOT more parts/pieces). You seed the file using super seeding. Here's what happens:
You start uploading part 1 to person A. Part 2 to person B. Part 3 to person C. These people then share the parts between themselves, so A shares part 1 to person B and C, B shares part 2 to A and C, C shares part 3 to A and B.
The result is that you uploaded 10GB once but now after you uploaded the file once the availability is 4 (you and three additional people) and these additional three people can continue sharing. Of course if you're limited by bandwidth at this point you would stop seeding and let everyone else handle uploading to other people. You could configure the torrent client to stop seeding once there are other seeds.
This only works if people actually help seed or else the torrent dies because the original uploader can't seed and the other seeds stopped seeding. I don't think this would happen here though because other people (like me) have unlimited bandwidth and can seed for longer times.
I prefer torrents too because it's more user friendly, no captcha/download limits (even with premium you have download limits), with torrents it's completely up to the users.
