http://restcountries.eu/rest/alpha2/za
The South African currency is ZAR, not SOS. Cape Town is the legislative capital, but not _the_ capital.
If you search by currency for ZAR:
http://restcountries.eu/rest/currency/zar
You get South Georgia. I assume that's meant to be South Africa.
And what about countries that use two currencies... oh wait, Cuba actually lists two currencies; never mind.
And what about countries that use two currencies... oh wait, Cuba actually lists two currencies; never mind.