It’s impractical in a setting like Iraq or Afghanistan, sure. On the other hand, if the Marines were to land on one of the Spratly Islands or on the coast of Norway, they could construct an airfield and have the Navy supply it from the sea, freeing one of the carriers or amphibious carriers to be redeployed elsewhere (or perhaps just adding to the local airfield capacity). Being able to base and operate STOVL aircraft days or weeks before heavier aircraft can be deployed there provides a significant advantage.