Robyn, minor detail here, but may have something to do with it. As far as moving dough around goes, a nonporous surface is at least for me not preferred. Take the aluminum peel for example, for me an absolute nightmare compared to the ease of use of a wood peel. I had to use much more flour with a metal peel, than with wood. For me, the perforated aluminum peel is trying to make up for its flaws. Some of this all dawned on me when someone argued the conventional wisdom of sanding a wood peel with very fine sandpaper, and instead said go medium. This gives bench/peel flour a place to be and minimizes surface contact with the dough. Sand it to 300 grit and it acts like an aluminum peel. Being a clean freak, it occurred to me one day to try a nice piece of tempered glass as a prep surface. It was the worst ever! As a prep surface goes, irregularity and porosity is a good trait, not to mention the temps that marble helps to maintain. Marble will help stabilize dough temps, if the dough is too warm, it can cool it, and if too cool can warm it. My 2 cents