When I first started baking pizza years ago, I read somewhere that one should toss some cornmeal on a hot pizza stone after preheating, just before putting the pizza on. Since I tend to bake pizza at the highest setting on the oven, the cornmeal (or semolina, which I later switched to) would immediately smoke and burn. I set off a smoke alarm in my house a couple times. And I always had this wasted layer of burnt cornmeal/semolina which I'd wipe off the stone after each use.
After a few years of doing this, I realized that my pizza dough never stuck to the stone in the oven (though I occasionally had trouble getting it off the peel as it was going into the oven). So I just stopped doing it. Even with the minimal amount of semolina I tend to use on my peel these days, I never have had a case of the dough sticking to either a preheated pizza stone or a pizza steel. (I have had cases where the pizza got stuck due to sauce or cheese leaking through a hole or over the side, but a little dusting of cornmeal/semolina wouldn't have prevented that sticking.)
Recently, I watched Alton Brown's pizza bake on his fun Mega-Bake Oven contraption. I noticed he too tosses what appears to be semolina on the hot pizza steel (which smokes immediately) before loading the pizza on. I've seen this recommended occasionally in other reputable sources.
I can certainly understand putting some sort of cornmeal/semolina/flour on a cold pizza stone or steel, for those who tend to bake raw dough without preheating first.
But is there really a good reason to throw some semolina or cornmeal onto a screaming hot pizza stone before baking, assuming a "normal" pizza dough (of some sort)? I would assume that perhaps some recipes might stick, though I tend to use a very high hydration dough that sticks easily to my hands and the peel, but it always releases easily in the oven. I also have baked many loaves of various kinds of breads and again have never had a problem with sticking.
Am I just lucky? Or are there some particular recipes/stones that stick more? Or is there some other reason for doing this?