I think cryptocurrency is just futuristics and easier to use because it is portable and secured compared to fiat currency that could easily stole from everyone and also could be destroyed.
But more like cryptocurrency is not yet used since the technology needs to keep up so that it could easily be implemented in the community compared to fiat money which uses already the traditional way.
In addition, what cryptocurrency has and fiat doesn't is the strong encryption of its data to the blocks, supported by its backbone which is the blockchain, that makes it possible to trust the system 100 percent unlike what the fiats have even if they have made their currency digital, without blockchain, transactions created from their platforms will not be as secured as cryptocurrency has and will possibly have, in the future. Furthermore, cryptocurrency could be serve as an investment because of the volatility it possesses for people to gain profit.