In order to use Popcorntime, you'd pretty much have to have a connection speed where downloading the movie is significantly faster than watching it (a few minutes at a reasonable speed/quality) and by the time the movie ends you have downloaded it once but uploaded many times.

And given the way the tech works, you can ignore ADSL users with restricted upload speeds and other similar groups - the total average is disproportionally influenced by high-speed users; so if for every dozen ADSL users there's a single FTTH user, then the total still works out well - 10 users with a ratio of 0.1 are equalized by a single user with a ratio of 10.

If you are streaming, you will very likely be downloading faster than you can play the file (people who download slower won't be streaming). So you will be seeding a lot longer.