It still fiat currency because it is still widely use by majority of the people. But bitcoin and other cryptocurrencies are gaining popularity around and even the global monetary authority like IMF had already notice the growing influence of the virtual coins.
The International Monetary Fund have already published a report about the possibility of cryptocurrencies could one day reduce the demand of fiat currency " by creating a shift from credit money to commodity money", in other words, the IMF suggests cryptocurrency could replace fiat currency someday.