It's a pity because we should be seeking solutions for both problems, money system allowing negative rates and private transactions. They should not exclude each other because both are important for different reasons.
all fiat currencies have number-go-down technology. look at a graph of purchasing power vs time for any fiat currency. It always trends towards zero.
start using a currency with number-go-up technology. look at a graph of bitcoin. instead of going down, the number goes up. you should adopt this type of currency.
I am aware this sounds stupid. I am also 100% convinced that it is true.