Univos - Universal World Dollars Currency

In this essay I propose a world monetary union in which all the countries of the world move towards a common universal world dollar currrency - the univos that is to be printed and maintained by a world body like the world bank.

Reasons for forming a world common currency.

The foreign exchange market is a zero-sum artificial market that enriches no one but the brokering banks.
It will eliminate US dollar and euro hegemony. Poor nations are funding the deficit of the rich nations the US and the Europe by accumulating dollars and euros. All these rich countries have to do is to print more dollars and more euros.
It will save jobs in the US and Europe. As USD and EUR are accumulated by outside countries, exports from these countries become unviable and imports become cheap leading to lack of sales for local companies leading to loss of jobs in these countries. If these countries shift to a common world currency there will be a level playing field for all the countries of the world.
Moving to a common world currency will eliminate currency exchange risk for all.
Most of the currencies of the world including the US dollar and the Euros are fiat currencies. Whats the problem with substituting one fiat currency (USD or EUR) with another?
There will be no need for a central bank for each country. And there will be no need for foreign exchange controls. The world will become one huge marketplace.
Having lots of different currencies, makes the subject of world economy, world finance a dense subject that very few understand. Having a common world currency will make it simpler to understand this world.
All the countries of the world and all the people of the world can start accumulating wealth in univos instead of individual currencies without fear of their wealth becoming devalued suddenly and mysteriously due to incomprehensible foreign exchange factors.