As soon as possible Cryptocurrency will replace fiat money transactions.
Because if it continues to be done in the future, then the paper money will consume a lot of paper, the paper will be produced from the tree, if the tree is cut continuously then Global Warming.
Trust me, my friend, the problem isn't the trees. Just before people had something of their own. And now, the state appropriated everything that belonged to the people and gave them papers, allegedly so it is easier to keep the property. And I think the cryptocurrency will be the next step, but so far do not know how to control it totally.