Not every operation that serves pizza makes the pizzas to order. Convenience stores and cafeterias may not specialize in pizza, so it makes more sense that they have a limited menu or have the pizza already made, for faster turnaround.
Conveniences stores and concession stands often have three or four different types of pizza on display in a specialized warmer that has round racks and humidity control, to assure proper freshness. Whether storing freshly washed pans or premade pizzas, it will benefit most pizzerias to have a few racks on hand designed specifically for pizza. Finally, some standard rolling racks are beneficial for most kitchens that bake a lot of food, because the racks will hold full-size pans of either ingredients or premade toppings and will easily roll around the kitchen or into a special cooler.