You can build a reversible payment system on top of a irreversible one, but not the other way around. Bitcoin allows mathematical forms of escrow. Bitcoin also

You can build a reversible payment system on top of a irreversible one, but not the other way around. Bitcoin allows mathematical forms of escrow. Bitcoin also allows extremely secure ways to store your cryptocurrency. You don't always want to log into your computer as root. But would you want a third party to log into your computer as root so they can watch and control what you do?