While cards are certainly convenient, they have failed me at very inopportune moments. I’ve also recently witnessed how someone could not book a ticket for a ferry in one of the mostly cashless European states - cash wasn’t an option and they didn’t have a card. This was at the official counter at the harbor.
A few month ago, card terminals of a widely used type failed hard in Germany, only cash payment was possible.
Being able to do some purchases anonymously is also a good thing - even if it’s only my wife’s birthday present.
I prefer a society where cash is an option for all (in-person) transactions. And preserving that requires exercising the use of cash.
Encrypted secure communication with (and within) the government, or my medical provider is entirely orthogonal to that.