Fiat currency will always be fiat currency nothing can replace it. One people can easily move it around, its accepted everywhere. Cryptocurrency is accepted in only few stores because some merchants cannot use cryptocurrency daily.
Crypto has not been widely used in my country yet, but in recent years a lot of big companies are starting to use this form of payment to make things easier. Of course this rate is very low and can not occupy 1% compared to fiat so the market needs to become stronger and investors have absolute confidence when using payment in crypto.