by 2022? in 6 years? Hardly so...
by 2030 - yes, very likelly.
by 2050 - VERY sure. Not even small doubt. FIAT will be found only in the history books by 2050
Maybe it will used by everyone in the date the bitcoin is widely use in that time. we assure we can found in history in our future user of bitcoin if that happen it nice to heard bitcoin is one of the popular and use in that year.
All this thing is depending in the fact that how bitcoin knowledge will be spread in this way that maximum people use this innovation and this s just beginning and so much people are using bitcoin for different uses and one thing is sure that in next decade the future of bitcoin will be more bright and many countries will use this coin so lets wait till 2022 to see how much people will use and get maximum benefits of btc.