In my country, there are holidays when bank offices are unavailable.
While you typically are still able to use ATMs and pay by card, any glitches you encounter can only be resolved after the banks open again.
In the past month I've encountered two such glitches: once the ATM debited my account but did not give me the cash, and another when my card payment errored out repeatedly and I had to pay cash.
Having some cash on hand can be prudent under these circumstances.
While you typically are still able to use ATMs and pay by card, any glitches you encounter can only be resolved after the banks open again.
In the past month I've encountered two such glitches: once the ATM debited my account but did not give me the cash, and another when my card payment errored out repeatedly and I had to pay cash.
Having some cash on hand can be prudent under these circumstances.
Everything was resolved by next day, however.