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.
Indeed, all that you have said is all true, and there is a big difference between the two kinds of currency, fiat as for daily use and cryptocurrency as for investment as what you have said, it is better to invest the cryptocurrency than fiat because cryptocurrency, as we all know, is volatile which means it changes its price day by day and that is why it becomes useful for investment, investment in cryptocurrency is more convenient compared to fiat currency when it comes for differentiating between the online thing to the manual stuff, it is always convenient in online, such as, gambling, lending, trading, as well as the investments. The idea in the real world is, it has so many processes before you accomplish all the things.