[Chris Williams]

CO2 is an independent system from the electrical, so it's not dependent on the state of the battery charge, or subject to the spikes and fluctuations of the other systems that effect the electrical system. It's also very stable wrt temperature and is therefore consistent in the amount of pressure applied to the system.

Finally, only with an air stop system can you control both the speed of on and off the stop. On isn't such a big deal, as most people just go on the stop as fast as possible. But you really need to be able to adjust the speed it comes off the stop. With an air system you can come off the stop smoothly and at the exact rate you need to avoid wheel spin.

Hope this helps, let me know if you have any other questions.
Chris