They have been using these for quite a while to protect infrastructure that can't be defended directly. During the Rough Fire in Kings Canyon, they wrapped a bunch of buildings before they evacced. Same last year with out sewer plant and well head.
I looked into what it would entail to get one for the house. It's neither cheap nor light and there's the question of how you would actually deploy it quickly.
Plus, there's another issue. The worst case in a wildfire is not that your house burns down, it's that all your friends' and neighbors' houses, your water supply system, sewage treatment system, power and phone lines all burn down and your house DOES NOT.
That was actually our biggest worry last year - to lose everything *except* the house and be stuck with no insurance settlement and a house that has no water, power, sewer or phone. So in the end, I decided the better thing to do is to work to harden the general area and just take reasonable precautions on your own house.
Maybe if I had 50 acres, no neighbors and was off the grid anyway, I would go for a fire blanket.