When the switch is turned to either of the 11 or 10 points, it turns on the side marker lights represented on the switch. This was a courtesy feature for people exiting the car, to have illumination for traffic passing to be able to notice you easier.
No, this is a feature required by the German Road Traffic Licensing Regulations. When parked on an unlit, narrow street, the driver is required to turn on the park lights facing the street to make the vehicle conspicuous to passing motorists.
The US version of this feature is to use reflectors.