Not sure about Bitcoin. Maybe it's not tied to any one nation etc but its value obviously floats so it's inflation prone just like any other. So far I have not seen any real value in jumping ship from US dollars.
About that: official exchange rates rise and fall, but it's still the world's most stable currency and the unofficial 'on the street' typically is higher than the official exchange rate. Like this: in Mexico several years ago the official rate was something like 8 pesos to the dollar. Unofficially 'on the street' it was worth 10 or 11 pesos even in restaurants, bars, stores etc. Not sure I want to toss that in favor of a currency which is in large part used as a workaround for money laundering.