Cream is better than milk, as most cats digestive systems can handle the butterfat.
Domestication has changed the behavior and appearance of cats, but not their digestive systems.
As cats evolved, their digestive systems adapted to accommodate the available food.
When they groom themselves they ingest the clay which can cause a blockage in their digestive systems and can be fatal.
As carnivores, high-carbohydrate products containing grains and cereals are inappropriate for cats' digestive systems.