Shortening is a highly processed product that is not healthy. It is vegetable oils that have been hydrogenated to turn them to solids, in other words, changing unsaturated fat to saturated trans fats. A great deal of chemical processing takes place. Aside from that, shortning adds no flavor to your baked goods. While butter should be consumed in moderation, it is a natural poduct that adds wonderful flavor to baked goods. Shortening is engineered to have a higher melting point than butter, which can change the texture of a cookie, but this has more to do with baking temperature. For thicker cookies, decrease the oven temperature. I only use butter for baking.