It's to allow the driver to control the passenger seat for either more entry space for the front passenger or legroom for the rear passenger. I've seen them on a number of Korean vehicles, for the Larger vehicles, you certainly wouldn't need to move up the seat for entry as the rear space is big enough already. It's more likely to provide more legroom for the rear passenger for that chauffeured driven feel, I think. My Optima has a lot of space inside and when my wife is driving, sitting behind her is like being in a 7 series rear seat. This is more of an Asian thing, this is why we normally don't see this on vehicles sold in our markers. I'm fairly sure this is on the Genesis vehicles in the US market.