Just fyi, one of the benefits of booking flights via
DCL is that you can cancel those flights up until your paid-in-full date without penalty. And if you buy DCL's insurance, it will cover the flight as well as the cruise. So those are bonuses. The latter is especially useful if you'll be cruising during hurricane season. If DCL were to cancel or reschedule your cruise due to a hurricane, they would also take care of your flight.
Disadvantages are that you can't book first class, or deal with the airline directly.