I am surprised when I hear that bitcoin is better than fiat. By fiat, we most often understand the dollar. Because in the blockchain industry, bitcoin plays a role similar to the dollar in the global financial system.
But ... The dollar is an abstraction. The dollar remains the dollar in any payment system, platform, application. Bitcoin is both a coin and an “ecosystem.”
Any system (ecosystem) has its own cycle of development and extinction. That is, the time comes when its modernization is no longer possible and it is necessary to follow other principles and create something from scratch.
For fiat, dollar or other possible prospective unit of calculation, this is not permissible. Therefore they are an abstraction. The principles of their treatment and methods of transmission may change, but not the essence.