Welcome to the forum.
If you use several tiles superimposed on top of each other to form a total thickness greater than your single stone (with equal surface areas), the tiles will offer a greater thermal mass. This means that the tiles will take longer to reach a specified temperature, e.g., 500 degrees F, but they will also take longer to cool down. It's just the laws of thermodynamics. Having this greater thermal mass might come in handy when you are making multiple pizzas in a short period of time where you want to have the stones/tiles retain their heat longer. Even then, it's a good idea to limit the opening and closing of the oven door to limit the loss of heat whenever the oven door is opened.
Different materials may also affect the thermal capacity of a particular stone or tiles. As you may have discovered in reading the posts on this subject, not all stones or tiles are made of the same materials. I don't see any need to do it, especially for applications such as ours as home pizza makers, but you would have to study the different thermal capacities of different materials to know how they will behave in intended applications. This is a matter of greater concern to the folks like Baker's Pride and Blodgett who have to design the right stones (materials, size and thickness) for their commercial deck ovens.