AppleCare + is effectively an insurance these days, and you are correct it's only valid in the region that you purchase it, if you want to make a claim...that is , you pay the replacement cost.
The warranty component is international, where apple replaces or fixes the device under warranty.
My proof, bought my 5S in the UK with UK AppleCare + and had the device replaced in Australia under AppleCare . Same happened to my 6S plus, bought in Australia with AppleCare + and had it replaced last week under AppleCare .
Now had I damaged the device myself and wanted to replace the device, I'd have had to take it back to the country to where I got my AppleCare + , as it would be an insurance claim affectively.