"Country" is an elaborate mental construct required to classify people. It is in the same boat with religion and other pointless things that humans need to justify their worthless existence. People don't want to think for themselves, so they simply key into stereotypes before making their decisions. Stereotypes helps them make "statistical" assumptions and punish the majority.
That's why PayPal doesn't work in Nigeria, Western Union can't be sent to Nigeria in some places and a bunch of issues.
And about selling kidney in Malaysia, I have one useless kidney I won't mind trading, do they pay in Bitcoin?