Total removal of fiat from the society will do more harm than good.
No matter the level of technological development, not everyone will be able to embrace cashless transactions. And also, most services need to be paid in cash.
Indeed, removal of fiat will lead every economic states into harmful situation than being logically successful with it. Fiat has been one of the contributor of the efficient work of transactions and I think it will not help every community without fiat since it serves as medium payment and several successful transaction was done with this. I will not support any cashless society topic since loss will name after every forum user.