Let me give you a metaphor !
We all know our world, and us, as organisms breathing air - a mixture of nitrogen, oxygen, carbon dioxide and others. Can a human being breathe other air ? Theoretically yes, perhaps science can “modify” man, and make more important not nitrogen and oxygen (key elements of air, providing our life and processes in the body), but for example carbon dioxide (let's assume, although as an example, not very good for us

). Science has made such a man, and ? How will he live in a world where most people require nitrogen and oxygen as a breathing mixture ? That's right - it will be difficult for him until the environment changes - for example, the level of carbon dioxide will not increase to the level of nitrogen in the air. But by that time the rest of the world must also adapt, and switch to increased consumption of carbon dioxide, reducing the consumption of nitrogen, for example. This is how it is with cryptocurrency - as long as all suppliers of goods and services use fiat currency, cryptocurrency will not be able to replace fiat. This requires global and systemic changes