Using p2p for media delivery can help build more resiliant archives, and facilitate freedom of expression/speech
Current examples using webRTC are peer5 and peerCDN
http://webtorrent.io has taken good first steps toward evaluating what is needed to make BitTorrent? work in the browser though a finished product is still a long way off. All components needed to make torrents work in the browser are already in the spec and are implemented, assuming the bittorrent spec can be modified to allow tcp for DHT peer discovery.
MSE will come in very handy for streaming from torrent to a video tag
A suggested demo that will make people say, 'wow!' is using MSE to append video data from a live stream from a p2p swarm, though it is unclear how this will work with bittorrent.