The problem with that position is that holding onto your physical money doesn't make any difference in the scenario you're mentioning.
We already have more money in circulation than we actually have physical bills/coins to add up to- most of it is handled electronically. In the event of a large scale issue preventing us from accessing funds electronically, the paper money you're holding onto will be equally worthless.
The exception to this would be a very temporary cutoff of funds, as in hours long, MAYBE days. Beyond that, most of our financial infrastructure (and subsequently, our currency itself) is extremely likely to collapse; even restoring the power and networks involved beyond that wouldn't help, the damage already having been done.
TLDR: In the event of the collapse of electronically handled funds, the value of actual physical money is extremely unlikely to hold anyway. If you're really concerned about something like this, you would be better served to stock up on things with actual value that you could barter later.