Round pizzas are traditionally packaged in square boxes because it is more efficient and cost-effective for pizzerias and pizza delivery businesses.
The main reason is the square boxes take up less space than round boxes of the same size, which means that more boxes can be stored in a smaller area, reducing the cost of storage. Additionally, square boxes are easier and cheaper to manufacture than round boxes.
Another reason is that a square box can be folded flat, allowing it to be stored more efficiently and take up less space when it is not in use. Square boxes also stack neatly, which makes them easy to transport and store. This makes it more convenient for delivery and takeout orders, as it makes it easier to stack and transport multiple pizzas at once.
Finally, the round pizza can be placed in the center of the box, which leaves enough space for the toppings and cheese to avoid mess and make it more aesthetically pleasing.