Steel or wire leaders do not need to be used on braided fishing line. Braided fishing line provides all of the protection from the sharp teeth of predator fish that is required.
Some professional fisherman have stated that the only time they would use a steel leader with braided fishing line is when water clarity is extreme, generally more than 18 inches. This is from the belief that the steel leader is less visible. However the majority of professional fisherman note they see no difference in the fish bite rate when using only the braided line in exceptionally clear water with visibility at 20 feet.