Talk like an adult, at least if you are one.
How well other currencies work we see in the Russia-India Trade Relations. Russia must accept India Rupies for which the Russians can not buy one single thing they actually need. And the Renminbi from the Chinese are forced upon them at an exchange course so far from reality that it is easier to buy dollars on the black market for Russia. Iran and Russia do not even trade in money anymore as both currencies are so volatil and non-usable that they now do barter trade.