I think one thing that held further adoption of @peertube back is that almost every fedizen when passing along a vid in a toot, uses the copied/pasted vid URL inline in toot text.
Almost no one take the 2sec. to look up the URL in their Mastodon or other microblogging client, and *directly* interacts on the video, by liking and adding interesting discussion threads below these videos (and imagine all the cool cross-refs to recommneded other vids that could be made here).