The most convenient type of food, for storage and for feeding, is dry kibble. The food can be left out for the pet to eat at its own pace without fear of spoilage. In fact, many pet owners appreciate the convenience of filling a bowl with enough food to feed the pet for the entire day, if not days, in the case of cats that are left at home while owners take brief trips away from home.
Dry foods are absolutely a convenience for many pet owners. Food can be left out for hours, if not days, and not spoil. Dry foods are easier to store -- a large plastic bin with a tight lid is usually enough to keep the food fresh and safe from insects and rodents (and from pets) -- and is more economically cost-effective when feeding multiple pets. Dry kibble can also be used as an effective training treat and as a dental health supplement. Some dry foods are specially formulated and shaped to clean the teeth as the animal chews it.
Of course, dry foods do not provide as much moisture as wet foods do, something that becomes more important as an animal ages, when an animal is ill, and in dry, hot climates. In those cases, a wet food diet can be more practical.