It all depends upon the size of dough that you are making. In a commercial setting we are making upwards of 80-pounds of dough at a time. It is all but impossible to uniformly cool this dough as a single piece, but when subdivided into individual dough balls, it can be uniformly cooled without much problem, what this means is that all of the dough balls will be the same with regard to dough performance and finished crust quality. In a home setting, some refrigerators can cool a 3 to 4-pound dough ball without much problem, while others will struggle, so in this case dividing the dough into individual balls prior to placing it into the refrigerator will result in more consistent cooling of the dough. What this means to you is that when you make the dough again and manage it in the same manner, it will perform very similarly to the way it did previously. It is done in the name of consistency. I have also found that when I make my dough balls right after mixing and place them into individual plastic bread bags, I can turn the dough ball out of the bag into a bowl of dusting flour and open it into a pizza skin more easily than I can an irregularly shaped piece of dough. Yes, I could form those irregularly shaped dough pieces into balls and set them aside to rise again, but that takes additional time which I don't always have.
Tom Lehmann/The Dough Doctor