Storing these items in a space like a cabinet over the fridge works well because you often don't need access to them.
These pieces are invaluable when you need to take a dish to a potluck for a family gathering, but they can get in the way when it comes to storage, they can get in the way.
Since you only need these items once per year, storing them in the cabinet over the fridge keeps them out of your way in a storage location away from your other kitchen necessities.
Maybe you have a few specialty appliances or gadgets like a snow cone machine or a pasta maker that you don't use often but still want to keep. Store them over the refrigerator out of the way.