The IDC could be billed to your US address, which should satisfy many websites, but the card is administered from the UK and you may still have some problems. In particular the IDC is known to fail stringent automated address verification processes.

For example, TFL's Oystercard site rejects my IDC because the billing address "does not match", even though American Express shows that the charges were authorized and TFL will, of course, not tell me which field in the address has the problem.