Parmesan cheese is a different kind of cheese than the other cheeses. This is due to its taste or texture. It is due to how it is often used in foods. Most of the time, parmesan cheese is only sprinkled on food and it is not baked inside of food in large quantities compared to the other cheeses. If it is baked inside of something due to a recipe, it is only in small amounts.
Parmesan cheese is often sprinkled onto pizza right before someone eats it. If you are at a pizza shop, you will probably notice that there is a jar with shredded parmesan cheese in it. The cheese is usually chopped up or shredded so finely and it is rarely seen in slices.
Wait until the pizza is cooked and served. The proper way to add the parmesan is to bring a large cheese mill to the table, then offer parmesan to each person in turn, turning the mill to produce a fine flow all over the surface of the pizza.
But the reason for offering it in this way is that some like only a touch, and others like loads. It's like when you add salt and pepper, each to his own taste.