I don`t think that btc is more popular then us dollar because us dollars is in the market place so many decades and even people from countries that we don`t know even they exist have heard about usd
the value of the bitcoin is very high than dollar and also the rate of rising in the value of the bitcoin is very high. Dollar is a legal paper currency while bitcoin is a crypto currency and is not legal all over the world but soon some country will legal it. if the bitcoin become legal in world market, it will have more popularity than dollar in the world.