I was serious, Don. I am honestly unsure what the legal status of places like, say, Puerto Rico is. It uses the US$ as its currency, but it's not a part of the USA, is it, so if you had a credit card from there it wouldn't be a US credit card.
(And yes, I know that Puerto Rico isn't in the Pacific
You're absolutely right to be unsure about the legal status of the various islands around the UK - it gets very
complicated. Some are parts of the UK, some aren't. Some are in the European Union, and others aren't. Eg, the Channel Islands are a part of the UK, but not
in the EU and there's no VAT there.