Both does have pro's and con's which we can really make out some differentiation between the two but never ever in my thought on thinking that Fiat would be replaced by Bitcoin.
Its really an impossible thing to happen no matter what as long government do exist then its impossible for any crypto to totally replacing out fiat because people would really still
consider on using that stable fiat on most situations even though it does have criticims for most of the time but we cant really deny when it comes to relevance.
Bitcoin is better that fiat on lots of points but we cant really consider on completely replacing it no matter what.