We don’t want too many 3rd-party requests. It’s convenient but troubling the way Discourse embeds links. So, a YouTube video on its own line gets embedded here in the forum (but, of course, blocked if visitors have a third-party blocking plugin).
Specific to YT: I use mpv (and the browser plugin Open With) and otherwise youtube-dl in order to usually not load YouTube directly.
Just a note for consciousness raising for anyone unaware.