Individual wheel braking. A computerized ABS system can monitor all four wheels and detect when one locks up, reducing brake torque at that wheel, then reapplying it when it detects that the tire has regained traction. It's physically impossible to do that manually with only one brake pedal, no matter how much of a driving god you are.

I'm not a huge fan of computerized driving aids for track use because they make me question whether it's driver skill or the software that's getting me around the track. Still, you cannot deny that ABS, traction control, stability control, electronic torque distribution and other technologies are sufficiently advanced that they are a safety advantage, and when properly setup in performance cars, a performance advantage.