Since many people try to convince us that Bitcoin is a bubble and how we will lose our money eventually, I wonder if money is not a bubble actually. There exist economies in which money has a positive value in spite its market fundamental is zero. That means fiat money has zero value. Fiat money is a social contrivance. We take money from other people because we know other people will take it from us. In theory and practice the fiat money is a bubble.
Don't forget that some fiat money is secured in gold and in gems. So it's not so easy to say it's a bubble.
However, everyone know that governments are still printing fiat money, and unfortunately this is very dangerous for the global economy.