Fiat for daily use.
While bitcoin or cryptocurrency for investment.
It's the embraced use of cryptocurrency today but we have to spend it in the most possible way to enjoy it. I have used it to shop for many times but our society is not yet ready to go all-in with crypto.
I am sure in the future there will be many stores that provide payment via crypto so that it will be easier for us to shop there.
Indeed, Fiat is used for a day in my area to do important things because if it is with crypto money, some people will not know it so the application is still not done.
Cryptocurrency is used by many people today for long-term investments and also trading in the short term on the stock exchange to reap huge profits.