I think it's obvious, difference of fiat money and the bitcoin. If someone know the bitcoin, then I'm sure he will select a bitcoin, I also feel that bitcoin many benefits especially when sending and receiving money from different countries.
Bitcoins has not grown so much to spend in all places, so I choose both fiat and bitcoins. Bitcoins are basically as an investment because its prices are more volatile so I can make some good profit over the time. But for my regular purchases, I still need only fiat currency because in my country bitcoins are not accepted in most of the places yet.