I don't think it's silly at all. How many app are at Facebook's mercy that cost well over $30k? All of Zynga. I do see there is some risk, but there are certainly plenty of valid, legal reasons to use Bittorrent. I'm sorry, but I certainly think that this really is going the opposite direction of Dropbox's goal of becoming "the internet's file system". This just seems like the natural progression. Maybe they can port it to Google Drive.
I just don't see why products can be held accountable for their users' activity. Should we sue Dell because some guy had kiddy porn on his computer?