The flat bottom allows efficient heat conduction and a larger cooking surface for foods and fluids. You can distribute the food in the skillet due to the bigger size, but the high temperature may cause the food to burn.
While a well-seasoned cast iron skillet is practically nonstick, nothing can beat a true nonstick frying pan when it comes to cooking delicate foods that stick easily. Look for models that have stainless steel or silicone-coated handles, which are oven-safe, rather than plastic ones.