I'm not sure that there is a real advantage other than the fact that American Express does not charge the currency conversion fee. Also, their blue card is like any other regular credit card. With this version, you can carry a balance. Of course, as pointed out, there is still the question as to whether or not retailers in the UK will accept. Thinking major ones will, but I could be wrong. Either way, wouldn't get rid of your regular credit card until you have a UK one. Paying the 3% sucks, but walking around with a large amount of cash all the time is not a good idea.