I mean let's face it, it's easier to handle money electronically than with papers in the hand. And if we compare fiat on the bank account and the blockchain money guesses who have the advantage...well not quite yet, but the potential for the blockchain is huge.
It is not always more convenient to work with electronic money, although in some cases they are better than fiat. These two types of currencies have their advantages and disadvantages in use and will only go together. Cryptocurrency will never replace the national money of states. Cryptocurrency can not interact with the economy of the state, as national money does. In addition, the cryptocurrency has a high degree of volatility and, due to even these two reasons, it can never replace the usual currency.
Fiat currency has been there for more than a century and still it is working. You cannot call it a failure so easily and it will not be completely eliminated. Digital currencies are better and good but not everyone is at ease using them. Also you need technology to be able to use them unlike fiat which even an illiterate person can use easily.
Fiat money fails in something simply because of its regulating body and of course the status of the economy of every country that dictates the value of their fiat currency, but we cannot eliminate fiat money easily which is still offers a more convenient way to buy and sell goods locally.
the more printing fiat currency will cause inflation and fiat currency to decline in value. if this happens to the dollar then this will affect the world economy. and the ups and downs of fiat money are also influenced by the government's political conditions and negative issues. maybe because this is why satoshi created a decentralized bitcoin so that it wouldn't experience inflation. if the fiat currency situation gets worse maybe in the future cryptocurrency will replace it.
The future of cryptocurrency is there of course but I think it would be better if fiat money and cryptos will stay together and provide us a more convenient way to transact around the world, which is good for us of course so let's keep on supporting this two monetary system especially with cryptos.