Fact: Dough, like pizza dough, when baked on a stone surface will finish crisper, browner and more satisfying than if it is baked in a conventional oven or on a metal pizza pan.
Why: Pizza stones and brick ovens (in this case the Big Green Egg) have a very extreme heat capacity (the ability to take a lot of heat without its temperature going up a whole lot). The stone has a higher heat capacity than most metals.
A good pizza stone also has a "vastly superior emissives" Infrared radiation i.e. heat, in a hot oven is "absorbed by the molecules of the materials that it strikes, which then re-emit much of the radiation almost instantly." Even when brought to the same temperature, the pizza stone emits more infrared radiation "striking the dough which results in better browning and crisping of its surface."
Conclusion: ALWAYS pre-heat your Big Green Egg Pizza Stone! The porous surface provides the additional advantage (on top of the emissivity) of absorbing the steam emitted from the bottom surface of the dough thus keeping is dry for more effective crisping.
 Paraphrased from 'What Einstein Told His Cook 2', Robert L. Wolke, W.W. Norton and Company, Inc. Ibid Ibid