Try it.
Even a small amount of powder will eat right trough bare metal, and it will destroy all electronics in it's way/ surroundings.
It is very effective in putting out fire, but it is devastating for most materials afterwards....!!
Foam on the other hand is cleaned/ washed of easily, but you need more of it to put out fire indeed.
Some years ago my Alfa got fire in the engineroom, when I stopped the car and opened the bonnet, flames were present.
A truckdriver approached with a powder distinguisher, but I send him away, and putted out the fire with sand from the road, and my bare hands.
I still own the car....!!
My brother bought a brandnew Mini back in 1990, three months later someone set it on fire ( at night, never found who did it though), it was put out by the local firebrigade with powder.
The car, beiing almost new, was not a total loss, despite heavy fire damage, so it was all restored, resprayed, new interior etc.
Within two years, the car developed all kinds of electrical problems, and worst of all, it started rusting VERY badly,due to the salty powder residue, the car was almost 4 years old, and was send to the scrapyard, beyond repair...!!
