I think the point is more "set a preferred default resolution" than "default to least BW".
I increasingly use youtube-dl for YouTube, Vimeo, and a few other sites. I prefer watching videos using something other than my browser, with uniform controls, the ability to speed up (especially talking head crap) and slow down (um, explosions and crashes) video. Preferences and commandline options can be used to specify preferred resolution, though HD can be really nice.
