Well yes it is a starting point, but pretty pointless relating to speed cameras, the whole point of it is a audible warning, as if you are speeding, you will not be certainly gazing at the sat nav map. I must admit I am rather surprised at all of the manufacturers they would sell a hell of a lot more sat nav systems with new cars if they did have it.
But camera detectors/alerts are illegal in some countries... hence why they are currently left off by the manufacturers