Such races are analogous to the weekends we will begin taking in Savannah to practice for sailing around the world. The Sprint triathlon provides a way to experience all the same actions as the Ironman race, but compressed into a 2 hour period. This is exactly how our weekends in Savannah will become. 3 days out on the boat will micro tastes of the trip to come. As August rolls around, we will start taking week long trips on the boat, adding even more to the tune up experiences.
Going for the full distance, even if one has done them before as I have with my past Ironman races, without some tune ups increases the odds of encountering problems. Lower the odds, practice in small containable periods. Plus, you get all the joy of doing what you love.