Markets are down today over nonsense stargazing like this. If we lose cryptography, we lose everything in a sort of blackout level event like on Blade Runner 2049. It won’t matter what you buy or sell to. I see no signs we are even close to that.
If anything, you should be stockpiling food and guns. Or, who knows, maybe GPUs and DRAM. Physical possession of goods, not paper ownership of the same.
Debt only exists by the mutual belief of debtors and debtees that the alternative would be worse.