Don't conflate the concept of currency with the concept of capitalism.
One is a tool to enable abstraction of trading the value generated by labor, whereas the other is a system of exploiting labor to concentrate wealth to a minority class.
We can eat the rich via wholesale transfer of their value as currency to a democratic cooperative that uses it to fund a better society.
Maybe that's an idealist's view, but isn't it better than the current reality, Where we let schmucks like Bezos have little yachts to take them to their bigger yachts to their mega platinum plated ultra yachts, while a good portion of his employees aren't given sufficient break time and end up pissing in empty bottles in trucks on the side of the road.
You're conflating the two concepts by asserting the value of money (currency) will be somehow diminished, if the system and mechanisms designed to concentrate it into the hands of the individuals (capitalism) were dismantled.
Why are you so certain that converting a company like Amazon from Private ownership to employee owned would necessarily tank the economy?
Focusing on making apologies for the system, saying "it's hard," and tearing down alternatives because "ItS jUsT nOt ReAlIsTiC" is neoliberal and not constructive either.