Exchange insurance and cruise insurance are two different animals. There's a lot more risk involved, IMO, with a cruise than with an exchange. For instance, if you luggage is delayed on a cruise, it's not like you can pop out to Walmart or Kmart for some cheap clothing. Rental wear for formal night alone can get expensive. Delay's in the ships docking when you return can add up to some expensive last minute airline tickets. If the airline doesn't get you to the port on time for departure, you either eat the cost of the cruise or have to pay carriers to catch you up to the next port of call. If you miss you're cruise departure, you also have meal expenses and hotel expenses to think about. Recently, I had to shell out close to $1,600 when the ship was delayed by 8 hours in docking and 113 hours before customs would clear the ship so we could get off. All because of a fisherman's strike in Spain.
Plus, the travel insurance company helped us locate a hotel room within 5 km of the airport in a city that was showing sold out on every other search site. Travel insurance does so much more than pay for the loss of the vacation.
Even exchange insurance has more coverage than the cost of the exchange. It includes travel delay, trip interuption, lost baggage and other coverages. Imagine getting stuck in FL for another week because you were trapped by a huricane. The extra costs experienced are often covered to some extent by your travel insurance.
Or suppose there is a thunderstorm or snow storm at a connecting airport causing you to miss your connection and you can't get out until the next day (I've had it happen twice now). Airlines often don't just provide you with a hotel room. The best I've had any of them do for me was to provide me with a "reduced" cost room. Sometimes those aren't so great if you know what I mean. Travel insurance, even the exchange insurance, will often cover the cost of the hotel room and meals if you're delay is over either 6 or 8 hours (I forget which).
Travel insurance, even exchange insurance, is so much more than covering the cost of losing the trip.