@hms-serapis Similar points to @insaneHoshi
Carriers give better fleet defense. Planes on island have to have an airbase built, and then only 3 fighters can scramble, and then even with radar, you still can’t scrabble tactical bombers.
Also, you have to capture an island the turn before you can land planes on it. So unless you have some very good ANZAC forces that don’t mind doing all the heavy lifting, you have to leave your fleet one turn ahead of your planes. (Reinforcement of captured bases only applies for the Marshals and Carolines.)
Range is better on a carrier. You don’t have to exit the island, and you can land where you don’t control islands. (See above point.) With a land based plane, you need Long Range Aircraft and and airbase to hit an island in the next sea zone. Or you can use a carrier. Carriers are needed to get effective island hopping going, as bombards only go so far aginst a determined Japanese militia spam.
Also, MAP off a carrier is so much better than MAP off an island.
Carriers are capital ships, meaning they give you hit points to take in battle, and are essential for a American VP.
Also, there is not always an island there. The northern Pacific is rather short on islands. And carriers can move to respond to threats. Islands can’t.
Carriers definitely have a role in maximizing the efficiency of an American push, and that should be the cornerstone of all US strategy, no matter the theater. Making the most of the short time the US is in the war is the best way for the Allies to achieve a victory.