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...
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.
As an added benefit, no bank knows where I bought and when, which I find is a great advantage over the alternatives. (I also use Gpay; this comes from someone who just found a good middle point without forgetting about the more reliable, physical and privacy friendly option)
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.
Nahhh - some banks have some parts of the infrastructure in COBOL. Specifically larger retail banks often have their ledgers in COBOL. Most of them want rid and are actively getting rid. Most places have had programs to root COBOL out since before 2000, but there are residual implementations remain. The ledgers are the hardest place to deal with because of the business case as well as the awkwardness. Basically there's not much of an advantage (or at least hasn't been) in modernizing so keeping the thing going has been the option. Now people want to have more flexible core systems so that they can offer more products, although not so sure that customers want this or can consume it. Still - it supports the idea of modernisation so not many people are keen to challenge.
The most common big implementations I come across are in Java.
Anyway point remains, electronic transactions with no internet or electricity is a solved problem, and banks don't want to solve it or they can't due to incompetency or maliciousness.
Currency transactions worth their weight in gold, it is of utmost importance for transactions to always be published to a central authority right away. If they don't have to be published, they should not exist at all. Imagine people buying stuff without anyone knowing right away! That should never, ever exist, for any reason.
[1] https://thenextweb.com/news/ancient-programming-language-cob...