To me, this is not even a question. Paper money has already started dying and has no future. Even if we let aside cryptocurrencies, even the regular fiat has come into the digital mode entirely, with mobile app wallets making the transaction of money a lot easier compared to paper money transactions!
The market of paper money has been adversely affected and that is only because of the introduction of digital currencies. If all the crypto currencies which are there in the modern world gets legalized, then there are chances that the existence of paper money remains no more. Most of the people amongst us will go for using crypto currencies instead of paper money.