The idea, as I understand it, is that a driver is cheaper than a parking space in someplace like Beijing, so you get driven Monday to Friday and then go for a drive yourself whenever else you feel like it.
Seems a bit dumb, as if you had the kind of scratch to buy this car, you could also buy a 911 Turbo for the weekends. I imagine they sell them to Porsche fans who have a collection of classic 911s and also need to be chauffeured around from time to time.