For two reasons:
It makes engines run better. It makes engines emit less hydrocarbons, soot and opacity and all other emissions into the atmosphere.

When added to fuel, CCT® raises the fuel's octane level. Octane is a measure of how much a fuel can be compressed before it spontaneously combusts. The higher the octane number, the more the fuel can be compressed before it explodes.

Fuel is mixed with air in an internal combustion engine and then compressed before it is ignited. An explosion will result, pushing a piston which is attached to a connecting rod. The connecting rod is attached to a crankshaft, which changes the piston's up-and-down motion into a circular motion. This circular motion makes the wheels go around.

Engine Performance: As far as an engines performance is concerned, the more compression available the better. Higher octane fuels can deliver more power for cars designed for high performance and speed.

High Performance Vehicles: If a high performance vehicle uses a lower octane fuel, the fuel might ignite during compression. The results of premature ignition during compression is a knocking and pinging sound emanating from under the hood that results in engines poor performance and premature damage.