Baha'i's can do well to understand the PURPOSE of a world currency. State currency is not for barter, never has been. As a "medium of exchange" State money can (and does) serve such purposes, but this is entirely secondary. State currency has been the dominant form of money for thousands of years, it has no intrinsic value, it is valued only because of imposed tax liabilities, fees, fines, tithes and levies. it is a way of accounting for credit + debt. This is the age old (at least 6000 years of human history) story of money. It has never been about barter or stored value, it is about reciprocity, a formal trusted accounting of credit + debt (we tend to trust authorities more as history proceeds, in the ancient past is was not so much trust but raw feudal power). The human sense of obligation, of giving someone a gift, and having a memory of this as a debt they owe you (or that you spontaneously forgive, since it is a gift) is ancient, a human primitive, and predates any system of money tokens. But money is the formal tokenized way we record and account for credit & debt since our memories cannot handle records of all our social obligations, money does it for us. it is not primarily for commerce, it is for spiritual purposes, accounting for our obligations.
A world currency would serve the purpose originally conceived of by John Maynard Keynes, which is to balance trade accounts so the resource poor nations do not lose their import capacity. It is about debt forgiveness, not barter, not storing of value. It is about justice and humanity, ultimately.
If you cannot afford his books, I highly recommend reading Randall Wray's blog series:
1. http://neweconomicperspectives.org/2014 ... olicy.html
2.1 http://neweconomicperspectives.org/2015 ... blics.html
2.2. http://neweconomicperspectives.org/2015 ... t-two.html
3. http://neweconomicperspectives.org/2016 ... art-3.html
4. http://neweconomicperspectives.org/2016 ... rency.html