Maybe bitcoin can not replace fiat, but surly it can complement it.
Because its easy to transfer bitcoins to any place in the world and convert them back into the local fiat.
The term i am looking for is the term that you just coined. It is the word complement. Well many are arguing about bitcoin against fiat currency well in fact there should be no conflict between the two. They should be in harmony and should be complementing with each other. So bitcoin cannot replace fiat currency but instead complement and support fiat currency.