In my humble opinion, I'd accept Bitcoin as a global currency. This is owing to the fact that the use of Bitcoin as a legal tender is wide spread to almost every nation across the globe.

However, some countries are still in the denial stage and hence have outlawed the use of Bitcoin and made trading the currency a criminal offence. But the enlightened one have accepted it a the next global currency and are already utilizing its potentials to the fullest.

I chose Bitcoin not because of its volatility but because, its a cryptocurrency that heralded the popularity of the other cryptocurrencies and even made the word cryptocurrency find it's footing in the finance and money world.

Making Bitcoin a global currency would not be any different from what we have today only that it would have legal backings across the globe and people would be able to trade freely with the cryptocurrency without fear of arrest from any government and without superiority claims of one indigenous currency over another because Bitcoin is not particular to any country