anything that disrupts the power grid or the internet neither of these assets will have any value based on "industrial use" as no industry will remain and buy them.

Silver is an antibiotic useful in many settings (including silverware, which is one reason the wealthy have long used actual silver utensils, and water purification, treatment of infection, etc.), and then there's coinage and jewelry, all of which kept silver valuable for thousands of years before James Clerk Maxwell began futzing around with electromagnetism. Several of the other many uses for silver would also be useful after TEOTWAWKI and in building back to levels of modern technology.

Much the same can be said for gold (although not the antibiotic effects): coinage, jewelry, and many other uses made gold valuable long before the Pyramids were built and will continue to do so long after you and I are gone.

I agree with you that blockchain itself can be useful in many areas, and at this point the security aspect is a strong attraction. And it may be that Bitcoin or other crytocurrencies will stand the test of time and even prevail. I wrote this post mainly because I see so many people pinning their hopes (and perhaps their life savings) on crypto without having considered the possible downsides -- there always ARE downsides, including of course for metals or any other investment class.