Popcorn Time (or the next leeching app) isn't good for torrents and sharing in general. If everybody switched to this type of software, there won't be enough seeds. Or maybe seeders will predominantly be those with some commercial interests (malware, ads?); and torrents will no longer be truly peer to peer.
Add: The old FAQ is gone, but quote from http://www.ibtimes.com/popcorn-time-movie-streaming-netflix-... : "According to Popcorn Time’s FAQ, you do indeed seed (upload) parts of the movie while you watch. Popcorn Time does state that ‘your movies will stay buried in a secret folder somewhere in your drive until you restart your computer. Then it will be gone for good.’"
Add: The old FAQ is gone, but quote from http://www.ibtimes.com/popcorn-time-movie-streaming-netflix-... : "According to Popcorn Time’s FAQ, you do indeed seed (upload) parts of the movie while you watch. Popcorn Time does state that ‘your movies will stay buried in a secret folder somewhere in your drive until you restart your computer. Then it will be gone for good.’"