fiat already made real money disappear, bitcoin, however can make fiat money disappear, if you check your history, we use paper notes, in order to but goods and services because it is much easy, rather than carrying around with you gold coins, silver coins or copper. back then, there was only barter exchange, it works like if you have an apple, and you your neighbor has oranges, you trade your apple with them for oranges and it will depend on the both of you how many apples will you give for a number of oranges, if your neighbor wants oranges, then came along the coins, which is the first rel money, people will trade gold coins, silver coins or copper, just to have goods or services, in which majority of the people accepted that the trade can be done with those coins, then people started to create banks, and within those banks the gold that you deposited, so paper money or notes have a value, for example if you have an ounce of gold in the bank back then that has a value of 2 USD, you can use your notes to pay others, and without having the trouble of going into a banks, opening the vault in order to get your gold in exchange for goods and services. the paper notes however, lost its value when the dollar was taken off the gold standard and they used it as petro dollar, which became the fiat money today, it is not backed up by any other commodities, it is just used as a basis to trade for oil, the value goes up and down, depending on the so-called stock market, which we all know can be manipulated, then the banks just started printing out money, without us having any idea, why do they print paper which has no value, but just a basis for exchange. however for cryptocurrencies they can make fiat money obsolete, for example if all countries in the world will use bitcoin for transactions, there is no need for banks, however today, we still need to exchange our bitcoins to fiat, just to see its value, but when the time comes and banks began to close, cryptocurrencies will take over, specifically bitcoin, being the dominant cryptocurrency, fiat money will just have to make an innovation in order for it to survive since bitcoins along with other cryptocurrencies, can be use for exchange of goods and services.