I'm pretty sure that this song's mixed up with being jolly and "emotionally- downed-upon", but for others (who do not have the same thinking as mine) well, not sure that would be likely a "joke" or ...

The currency value of the SDR is determined by summing the values in U.S. dollars, based on market exchange rates, of a basket of major currencies (the U.S. dollar, Euro, Japanese yen, pound sterling ...