All of Vincenzo's questions are best answered by "It depends on the circumstances."

In every case I know of ( cancellations due to health,weather, civil disaster, air evacuation) the policies available to UK (and perhaps Oz, NZ, SA) residents have been more comprehensive and cheaper than Americans can buy.

Circumstances? Huh? So a hotel that's closed because of hurricane damage wouldn't provide a refund under some circumstances? An airline that cancels all flights to a destination wouldn't provide a refund under some circumstances?

And, AFAIK, it's pretty universal that the insurance kicks in only in case of an actual event that causes those cancellations, and not just because you suspect there will be a problem.

But maybe I'm misunderstanding the comment.