Even cash breaks down pretty quickly in a hypothetical situation where you have something similar occur that lasts for an extended period. When banks' systems are impacted, how do I get more cash from my account with them when whatever amount I had when the system went down runs out? I haven't had a physical passbook for an account in a good 20 years.
This ordeal has made me think, I think I'm gonna just pull out $10 a week from my check and put it in a box, eventually I'll have a stash and if shit goes down at least I'll have that, and I already have a small collection of silver (and uhh....brass, copper, and lead...) that I could trade for things.