This is indeed a great and little known feature of Mac (though it's an optional install). Great for troubleshooting and the occasional excuse when you really don't want to share video.
If your behind a router with QoS features, learn how to use QoS.
True but the NLC you can click on and off on the spot at a moment's notice. Beats logging into your router and fiddling with stuff which often needs time to update.
I suppose you could join via the web, then use the Chrome dev tools bandwidth throttling. Not sure if it works on webrtc and websockets though.