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.
We don't really know what new technology may come out in the future though. It's possible that somehow in the near future, everyone will have instant access to a bank account or some form of savings account that they can use instantly with some piece of technology. For now, however, I agree with you that the removal of fiat would not fare well with society.
The entry of crypto currency in the trading market change the out look of business/ financial community globally. The FEAR of unknown was very much visible in the business world or the financial community. Yet, with the growing acceptance of crypto currency transaction in the trading market, it lessen the Fear instead it was replaced by openly talking about the crypto currency investment in the trading market, what coin are good, with stable fundamentals, does increase the awareness of this digital crypto transaction in the trading market. We don't know if the FIAT money will be extinct in the future of trading market or even local circulation, Banking system will be affected and the possible effect on the Economy of the its country which is unknown to everyone. The time to replace the FIAT maybe not now, global market is not yet ready.