You initially indicated that tank air is REQUIRED for inflation at surface. That was erroneous thinking, glad you corrected yourself.
"an emergency on the surface MIGHT require gas not just for breathing but for inflating a BC"
I stand by my initial phrasing, and my larger point about not surfacing with 200 PSI.
And if you are ever trying to keep an unconscious diver afloat, just hit their inflator button and then ditch their weights. Even though you are skilled in the art of oral inflation.