Many of us fall for the marketing...I have no idea how such a diet would affect your animals...all I can stand on is that the corn products are not good for them. You have to watch for corn and other unhealthy 'fillers'...
My vet, who is a cat-only vet and who breeds Main Coon cats, has always said that a dry diet was fine. Guess like human doctors, they don’t always get nutritional training.