You're right, in an ideal world it would mean nothing, as country distinctions are mostly arbitrary. However, there doesn't exist, and most likely won't exist in the near future, a world government that can realitistically replace all of the country governments, which is why it's not worth calling for the imminent removal of 'country rights'.

However, in the case of states, there is a organizing body that can, and is increasingly governing in their stead -- the federal government. And as many people believe the federal government has on average done a better job, that is why there are calls for the retirement of the 'states rights' concept.