Even if you have cash many shops would not sell anything in case of a mass outage because registers are just clients which depend on a cloud to register a transaction. Not reliable but cheap when it works.
And who's fault is that? Why did europe allow this?
Why will the US allow this, eventually?
In Spain it's now illegal to pay with cash for transactions over 1000EUR. Absurd.
In Norway they recently made it mandatory in most circumstances to accept cash for transactions up to 20,000kroner (~1700EUR): https://www.norges-bank.no/en/topics/notes-and-coins/the-rig...
You can do as many electronic transactions as you wish without internet or electricity, provided you have something with charged battery. Problem is the transaction cannot be verified without internet, but when internet gets restored, all transactions can be applied.
That technology exists for more than a decade, so banks will implement it in 20 or 50 years. Most sane people will not wait patiently for half a century till some software engineer implements electronic transactions with COBOL, and we will use some kind of blockchain much sooner than that.
I don't know how true the relationship between the cashless lifestyle and safety actually is, but it works and I feel ok; I'm not sure that the prospect of a few hours of national blackout once in 20 years will make me change my mind significantly.