You mean like a fiat analogue of Bitcoin? But why would anyone do it? There's a certain amount of $21M of Bitcoins which eliminates the possibility of inflation. And if it will be cash - it can be indefinitely printed, so BTC will lose its value. And there will be no more anonymity. I like another tendency, making real money into cryptocurrencies, like Tether, but not vise versa. Cryptos are the future.