No matter all it takes fiat will still be over bitcoin but if there are some cases were delay of payment is then such people or individual may decide to pay using bitcoin. But one thing for sure is that both bitcoin and Fiat will be in full usage non will be left behind, as a matter of consideration bitcoin can't fully function without fiat they both function together. Let say, for one to acquire bitcoin they needs dollars or fiat then sell to bitcoin same it's to when someone have a bitcoin wanting to sell to fiat.

Bitcoin is never created to counter fiat rather was created to support and ease payment for people where will be delay for fiat to scale through then bitcoin is being use to ease the payment and break every limitations.