It's about being able to pay for basic needs (rent, bills, food) via cash.
This is not some impossible crazy thing. Cash was used for >90% of purchases including weekly bills not that long ago whilst skyscrapers and big business deals didn't involve briefcases of cash being thrown around.
If you want to argue for a world where said attack vector isn't possible, then you're implicitly arguing for a world where people literally stash money under their mattress as a standard model of security, but that implies constructs like mortgages can't exist. Point being, how money is represented has a big impact on how society is able to function.
I mean, if that's the only scenario you care about, you can just carry more cash in your wallet.
But when you said "a system that allows governments to arbitrarily "turn off" thousands or millions of people at the push of a button", that sounded like you were worried about more than just not having enough money for groceries for the week.
One thing many don't realise is just how difficult the banks have made this for us now.
The money supply consists of three parts: physical cash, digital central brank reserves, and digital private bank money. This is how it is in the UK, but the US will be roughly the same.
Physical cash, everyone knows. It's printed (and destroyed) by the government. Digital central bank reserves exist in a ledger kept by the government which private banks use to settle up every night (to handle inter-bank transfers). Digital private bank money is money created by private banks when they issue loans. It is what exists between someone taking out a loan and paying back the loan.
Digital bank money is about 80% of the money supply. Central bank reserves about 18%. Physical cash: 2-3%.
The banks have inflated the money supply so much it's simply not possible to live with cash for most people any more. Assuming someone pays rent, it's not unusual to get paid in digital bank money and for 40% of that to be digitally transferred to your landlord. None of this ever becomes physical. There simply isn't enough physical money to go around.
How do we stop this? It would take a huge government intervention and a brave one. Society is on the brink of chaos at any moment and everyone is too afraid to rock the boat.
I'm 39; so maybe too young to have experienced that but how does it even practically work? Did your landlord pop round once a month? For utility bills, did you go to the bank and ask them to transfer cash to a utility company; or maybe at a post office? Or did the utility company send someone around to collect cash payments?
I have a bank account. You give me £100 and tell me to send £100 to 00273 00338435. Done.
As other posters have said, in many countries this is a Service(tm) but generally, unless you've gimped payments anyone can just do this.
Bills - Pay in cash at the Post Office
In Australia I still see people in Post Offices waiting to pay their bills. Some simply haven't got out of the habbit yet..
All fiat means is that it is unbacked by physical things, such as gold or silver.
Fight Club is satire.
I don't think you realize how cashless society really is. For a long time, we've been running on fiat money, debt, and other forms of monetary constructs that are, for all intents and purposes, just numbers in some database without the backing of physical bills. Imagine coordinating all of the stakeholders for a condominium building project with only paper currency; it'd be a madness only marginally better than bartering.
The idea of rejecting a cashless society is eerily similar to Project Mayhem from the movie Fight Club, with all the chaotic anarchy that supposedly comes with it.