[azernik]

For a country the size of the US? Yes, there is a MASSIVE difference between the two. The volume of movement by air between California and, say, Colorado is massively larger than that between California and China, and one of those places currently has a COVID-19 outbreak and one does not.

The distinction between the two for the sake of definitions is also very clear - whether the restrictions apply to travel that does not cross the borders of the United States. The currently-announced restrictions do not.

The question isn't of restricting external traffic in addition to internal traffic; we're only limiting external traffic. We probably need to be doing a bit of both, though with less draconian limitations on internal traffic to accommodate economic realities.