It is lightness in principle, even when speaking of consumption. Despite the fact that carbon-ceramic discs are quite larger than cast iron discs, a 5-6 kg reduction in weight can be estimated for each disc. Therefore the car is 20-25 kg lighter.
With lighter cars acceleration and braking times improve. In other words, less energy is required to accelerate or less energy to brake. At equal performance, the lower weight of carbon-ceramic discs - 50% less compared to cast iron discs - results into less engine power dispersion.
The reduction of weight obtained thanks to carbon-ceramic discs allows for a significant reduction of the unsprung mass of the vehicle, contributing to the dynamic performance of the car during sport usege with a better handling and fluid drive, all with a reduced fuel consumption, thanks to the engine power saving.