I was thinking that it may be the point. This is a service paid by Americans, for Americans, and I suspect they don't want to make it too convenient, especially for non-Americans.

From the link:

> The service will be provided at no charge, and user keys may be used to connect to any of the servers whose addresses are listed below. Additional hardware will be added in the future if the demand for the service is sufficiently great to warrant it.

Making it clear that they are going to shoulder the extra costs.

better question is will be they willing to mail you reply outside of usa.

if you really want it, there are plenty of services that provide you with virtual mailbox in usa