I have held a sample of it in my hand. It is very light, but not porous or anything like that. It is affixed solidly to the skin and I believe it could be easily gouged with something sharp however a 15,000 mile per hour wind won't take it off or damage it in any way. Air has a fairly good abrasive factor and is considered to be rated pretty high.
This foam insulation, I am also familiar with since my days in plant construction. It is also light, but porous. It is soft enough to squash between your fingers to nothing but a light yellow dust. It has no strength without it's coating.
Another observation.....When I had a office downtown a few years ago, a rat ran across the floor and sat in the fireplace. I kept a .357 mag in the top drawer at the time and I busted his little butt with it. The fire place was old and I was sure that I damaged the brick. What I found was the bullets barely made a mark and one brick (standard house type) was gouged about a 16th of a inch. This was at a 90 degree angle to the brick.
The things I learned about the characteristics of insulation and the time I held some of that insulation, (at the NASA plant in New Orleans, still a stock holder BTW), lead me to be skeptical, but not blind to this theory. It just seems hard to believe.
That's because the brick is a high density ceramic. It has a relatively high compressive strength. It's not very uniform though, so if the brick were on the table top and you shot it, it would crumble. When the brick is connected with others by another ceramic like concrete the stress is distributed, so the most of the brick is supported and all the compressive stress from the bullet is applied to the small area.
The brick is essentially incompressible, so as long as the energy of the bullet is insufficient to turn a cone of the height of the wall thickness into dust it will only make a partial cone. If you noticed, as you look deeper into that 1/16" hole the width of the damage was bigger. The outside, were the bullet struck was the same dia. as the bullet.
If you have a ceeramic that has a high void density, the voids are infinitely compressible. The structure containing the voids is collapsible. It's ceramic, so shear and compression forces only have to reach the buckling strenth of the walls, the films, and or fibers.
The urethane foam is a lot more massive and resilient than the silica layer on those tiles. The silica columns snap when the mass and velocity of the foam is big enough. The force would be the change in momentum with time, dp/dt and the compressive stress F/area. If the relative momentum is small enough, the foam bonces off, because it is resilient and the energy goes into deformation and rebound. As the momentum increases more of the silica structure is turned to dust when the foam has reached it's max deformation and the load on the silica is the highest.
On the atomic scale the momentum imparted by the moving air particles is not sufficient to knock the components of the silica out of place. These tiles also have a very thin dense outer layer of borosilicate, that behaves just like a high density ceramic for atomic impact purposes. Atoms wacking it might be similar to 22 rounds hitting hardened concrete.