Cryptocurrency is deflationary it can never be stable... If any one cryptocurrency becomes the de facto method of currency it will still take over 20 years for it to stabilize. And even then maybe never.

The currency is supposed to be international. Though the USD is stable inside the US, its value relative to the EURO is constantly fluctuating. Further the amount of goods you can buy with a set amount of USD fluctuates more than people think. And in crypto this would cause the value of the cryptocurrency to fluctuate as well. I mean more than 30% of the world don't have access to bank accounts, monetary value fluctuates all the time between countries.

If we want cryptocurrency to be used we cannot wait for it to stop fluctuating.. These damn wallets need to be set up so I can send a set amount of fiat to people and it just automatically, using market rates, gives them the appropriate amount of crypto.