On a site (which uses webtorrent) you can either serve ads (like youtube does), BAT (or equivalent) or have a subscriber model.

I would wage most people won't even know they are being served by the web torrent mechanism when you hit the page. The video player looks like a regular html 5 video player.

You can just point youtube-dl at a video. However the vast majority of viewers just use the site / phone app.