I can tell you why it is a good idea to have insurance... On the last few skiing trips I have been on we have had (either in our group or people we were skiing with on the day):
1 broken leg, 2 cracked ribs, 1 smashed shoulder, 1 bruise running from hip to knee(!) and 1 French lad we were skiing with fell about 30 feet off the side of a vertical drop.
Oh, and I skied into the side of a tunnel last February!
Before you ask, not one of these injuries was caused doing anything daft or unthoughtful. (I left the punctured lung off the list because that was silly.)
No matter how good a skier you might think you are, there are many, many injuries caused by others or by small tumbles when not expected.