Whatever the pros and cons of using a screen in the commercial context, I don't think they necessarily translate to making pizza at home. I can think of at least two good reasons to use a screen at home. First, it's a helpful guide for stretching your pizza to the proper diameter. It also helps keep a nice round shape. However, I've made probably in excess of 50 NY-style pies in the past year and have gotten really good at stretching my dough. So, I don't necessarily use a screen for shaping purposes (incidentally, while the shape isn't as important as the taste/texture, there's nothing wrong with being able to make a nice round, visually attractive pizza at home -- wonkier doesn't = better as a matter of course
).
The second reason -- the biggest reason for why I personally use a screen -- is that it makes it possible to
evenly cook the pizza to the proper doneness. Consider that the height of most professional pizza ovens (e.g., Baker's Pride) is probably less than half the height of your average home oven. This allows commercial pizzas to cook incredibly evenly. Cooking a NY-style pie that evenly just isn't possible in a home oven (at least as far as I've discovered). But I can achieve an evenness similar to commercial pizza joints if I start the pizza on the center rack of my oven (
on a screen so the dough doesn't fall through the rack), then slide it off the screen and onto the hot stone on the bottom rack (when the crust is cooked enough), and, finally, finish it under the broiler to finish cooking the toppings.