Well, the Queen, as head of the House of Windsor and Head of State of Britain and head of the Commonwealth does something a bit more than pomp and circumstance! No, the House of Windsor doesn't matter to most Americans as they're not in the Commonwealth nor are they British, obviously. However, the House of Windsor doesn't exist to make other nations happy or interested!
However, this thread is about Diana and her death was, I believe, as big a shock to Americans, especially adult females, as it was to the rest of the world. It certainly dominated the media there for days, including coverage of the funeral. As I've said before, an Aussie friend who was temporarily living in LA at the time of her death had complete strangers coming up expressing their condolences.