It certainly involved a lot of skill and expense, but how many more lives could be saved if the same money had been spent on improved traffic safety or NHS in general?

Probably not that many. You underestimate how expensive either of those things are.

We have obligations to provide services like this to the people living in our overseas territories, and you won’t find many people who’ll oppose that.

True, but this is military expenditure. So would you rather they spend this on an exercise or on actually saving people?