Webtorrent is very nice in web browser. But,i am not convinced why should i use webtorrent outside browser where i can use transmission/aria2/libtorrent based torrent clients.
WebRTC uses DTLS, and ISPs blocking it is a pretty high blast radius. Also with conferencing being so important makes it much easier to hide. Tor's Snowflake did some good writeups on this also.
WebTorrent doesn't require a browser to use either anymore, so you could see lot more peers if you use both!
Though your point is partially valid now that libtorrent has recently added support for WebTorrent protocol.
The ephemeral nature of tabs discourages reciprocity, so I don't think supporting browser use is good for preserving content availability.