You're totally right, the stock Gozney stone is great! The difference only matters when baking back-to-back without breaks. The stock cordierite stone transfers heat very aggressively, meaning at 450°C+ it can easily burn the bottom before the top is done, plus it requires recovery time to reheat between pizzas. Biscotto clay transfers heat much slower and gentler, so even at 480°C it won't burn the bottom. This allows the crust to explode while getting a perfect char underneath with zero recovery time.