In the event of a CME or EMP, which box store will accept crypto currency that you can't access?

Once again a flawed question, in the event of an EMP these stores can't take cards, which is what you use for bank payment, neither can they take cash because the register won't open and the inventory system won't work. The stores will shut down. However, soon as there is power, crypto works in all these stores.

If some electronic calamity occurred, do you think the farmers, the people with the food would accept a form of payment that just caused the calamity?

What the hell kind of question is this? It's the EMP or whatever event causing the power outage that is the problem, not digital currency in itself. Besides, you've completely missed my point. I've been arguing that no medium of exchange will work in such event.

You think the farmers will accept gold and silver? not being able to verify if it's real actual gold? Of course not, they will keep their food for themselves obviously. Bartering with neighbors is the best bet.

To take yours all they have to do is flip a switch.

Hardware wallet, it takes a wall of hot lead here too. And not only that, if they kill you they just take your gold, if they kill me they have to first find the well hidden device and crack encryption as well.

Tell me, which stores are you currently able to pay in silver at? And how many of those have a 100% paper based inventory system, cash registry, diesel generators for freezers, lights and other important infrastructure. You live in a fairy tale if you think your local stores will survive an EMP.