☞If Bitcoin was the currency of a country then what will happen?☜
It will not rise to a prominence like this. The limitation will be local, except it is the currency of US or EU.
Cryptocurrency is known as the fastest transaction medium for people around the world.
Where did you read that, what could be faster than just bringing out fiat from your pocket and paying for what you have just bought.
I disagree. You didn't consider countries where online fiat transactions are not advanced and those where the cross-border fiat transaction is a headache. I know what you are trying to say, but if we plus and subtract the point of arguments for and against, crypto still wins.