With crypto currency getting popular, it's also exposing the incapability and unsustainability of the fiat currency as a financial mechanism. While crypto currencies are based on computing power of GPUs, CPUs, SSDs or RAM, it's energy consumption is fair enough as compared to the resource consumption that circulating fiat currency incur. Here we are not talking about nature/types of cryptos but the superiority of it over the fiat system. I have found the following reasons to prove crypto currencies are superior and Sustainable enough as a financial mechanism than the fiat currencies:
Printing fiat currency (paper money) requires huge amount of trees to be put at stake for the material which is directly contributing in the deforestation process.
Then came the process of conversion from tree to paper which eats up energy, labour as well as various chemicals which later are drained into the environment causing alteration in the natural livestock balance.
After that, the printing process starts at a central money printing factory which are labour, energy and security intensive which becomes expensive with time and inflation.
Then comes the process of transportation of the printed currencies to centrally regulated sub-banks or its affiliates for regulation purposes which is carried out through fossil fuels operated automobiles/airplanes contributing in Green house gase emission and air pollution.
While fiat of one nation needs various phase of international regulations and network fees to intermediaries, crypto currencies are a global currency over which no government has control over.
Fiat is a financial mechanism where there needs permission at all stages of transactions from the regulator i.e., Government while crypto currencies are permission less environment and regulating authority being humans/public.
Most importantly, the regulatory authority of fiat currency as we all know are the central banks who control all the interest, cash flow and inflation/deflation mechanisms. That's reflects the control over the financial freedom of individuals by the centre and demoralise the democratic nature of a nation.
Keeping all the above factors/concerns in mind, it becomes clear and obvious that the newly introduced crypto currencies as a financial mechanism are way more sustainable and democratic than the traditional fiat currency system. It is true that it is energy intensive but that can be brought to a optimal level through renewable energy adoption after which there will be no flaws in recognising the crypto currencies as the most Sustainable and democratic financial mechanism for a nation to adopt worldwide.