[Edited to make it more understandable question]
What if all nation use only a one currency or one global currency?, What will happen to our world?, What is the effect of every nation's or every country economy?, It can make people's unite each other?Any opinion.

I think, that would bring a better world to everyone. A world where there is an equal currency, this could mean that there will be no more division between societies, third worlds would be no more and there might be equal opportunities for every one.
I think life will be easier to sustain since the price's of food or daily needs will decrease and in that case, I think that bitcoin will lose its value since it will be easier to live and there will be no more problem entertain since the currency is internationally stable.