Have you ever heard of "swamp butt" In AZ in the summer, you can drive all day long with the a/c blowing, but the sun beating down on you will just about kill you still. My saab 9-5 has ventilated leather seats, its amazing. It seems an option that once people have it, would never want to live without it during the summer.
If you've never had it, you'll never think you would want it... BUT once you've had it, you'll wonder how you ever lived without it.