If that happens, then Bitcoin will "stabilize" effectively proving its use as digital cash. With a country like El Salvador adopting Bitcoin as legal tender, we may be one step closer to "hyperbitcoinization".
To made all this reality Bitcoin need to stabilises itself first by fixing its shortcomings like price volatility, scalability and fee. Its not possible to made it to main payment system with such shortcomings.
Do you think it's possible Bitcoin will become a "global unit of account" in the future? If not, why? What would a world without Fiat really look like?
After seeing how big powers are reacting towards Bitcoin, I have zero doubt that governments will replace fiat with Bitcoin. We need to understand that Bitcoin is a complete financial system that can exist with current fiat based financial system.