Why Europe and the Pacific needed different craft

Why did the United States use different landing craft in the Pacific and at D-Day?

The oceans, beaches, reefs, and approach conditions differed, so each theatre rewarded different craft.

Landing craft are tools for particular water and beach conditions. American air-cushion craft suit Pacific distances and shores, while British LCUs align better with European requirements. Coalition operations may therefore require allies to share specialised craft rather than assuming every fleet's equipment is interchangeable.