Bitcoin is like Noah's ark for us. The time change, technology change and also people change. From fiat to bitcoin, it will become more and more useful thing but I still believe that bitcoin will not replace fiat currency. There's a lot of things to consider before it will happen if ever.
fiat can never be replaced by bitcoin. Fiat will remain the national currency and major currency. Bitcoin is just another alternative to a more revolutionary method of payment. Bitcoin and its technology make fiat even better. Bitcoin brings future technology that is increasingly being developed and various kinds of new innovations that use blockchain technology and cryptocurrency.