I've had banks go technologically tits up and render my funds inaccessible for multiple days in the past. Card payments fucked, etc.

Has happened to more than one bank I've used, in more than one country.

I've also had a bank freeze my account temporarily (for over a week) because some risk algorithm somewhere thought fraud was occurring.

All those times, having a bunch of cash handy was very useful.

As for hard assets: they make a decent hedge against financial shithousery.