lots of recent comments.....
Corrosive or not, I still wouldn't use it! I've had to clean an a car engine compartment after using one like shown and would not want to do that again.
not sure of the stats on this, but FWIW, I consider the 2 lb. BC in the baggage compartment for ground use, and that would be .......
engine fire on start, grab the BC, jump out, and use it on the engine, or ground if fuel spilled etc.....where a few seconds of a small Halon might not do the trick.
....or use on a neighbour's aircraft, hangar, or lawnmower etc.
as you say, perhaps some of the older, bolder types have some real-life feeback.
Can you level the plane, hold your breath, and fire a dry chem extingiusher in a cabin? Ventilate, clean off the gauges, and actually carry on with an emergency landing?