Both the Credit Card and the Charge Card offer good insurance, although with the Credit Card, travel arrangements have to be paid on the card to activate the policy, whereas that's not required with the charge card.
The Charge Card provides complimentary membership to Priority Pass for the primary cardholder. This gives you access to lounges around the world, including Virgin Blue lounges in Australia.
I just visited the AMEX site and they don't mention that you need the credit charge card for the priority pass membership, and it's a little confusing, but just to make sure, someone HAS to get the charge card for the priority pass membership right?