Why a Large rear wheel or small rear wheel for lawn mower?

Large wheels on the rear of a push mower is nothing but marketing gimmicks... infact most of the time it's worse because the rear wheels end up breaking. It's perfectly fine if your lawn if flat and you don't plan on turning but if you do or mow on any hills the side load normally wears out the wheels faster in the rear. It's nothing more than a gimmick. And makes it harder to mow the lawn especially if you have things you need to go under such as deck steps..etc.