It's been discussed here a few times regarding keeping some spare cash available, just in case. There's also the argument for keeping hard currency, i.e., silver or gold, for the in-between times. That's the period where paper currency no longer holds a value, yet folks aren't ready to barter only for tanglible goods, like food and ammunition. It could be argued too that hard currency will have value in the recovery period, after the SHTF. Tom Sherry's "Shattered" novel series illustrate well the use of hard currency in an extended recovery.
Anyways, here's an article regarding the need for cash:
https://www.ammoland.com/2018/07/when-your-credit-card-fails-to-work/ Credit Cards and EBT cards are certainly weak links in modern, first world society.