I'm curios guys what if after a centennial years all around the world using cryptocurrency to pay they didn't use a real money

newbie here

In my opinion this is going to be the future. Crypto currencies are great to connect people all around the world. Transactions fees are so much lower compared to the standard banking fees. Just one thing, why you say "use real money"? Crypto currencies are real money. Just look at Bitcoins. You can use bitcoins already in so many stores to pay for things.