Some people would prefer scaled down quality instead of stuttering when watching eg. live streams or on-demand movies (and not have to wait for download to finish).
For on-demand movies, I'd like to it to buffer in advance to a sufficient time length, but don't stutter anymore after that!
Hell I would rather lag for 1 minute for live videos instead of DASH.
I think it boils down to personal habits, would you endure constant small problems with quicker progress, or would rather suffer at the start and enjoy a smooth ride afterwards.