The dual zone climate control is what you have there. The side vents and footwell vents will reflect the zone temp set by the dials. The dial at the top is for the centre vents to quickly choose between heating or cooling. It's a great system unique to BMW still I believe.
So the temperature displayed is only a thermostat for the side (near the doors) and foot vents? The don't affect the middle two? Hmm.
I can sort of see how that would be useful, but I'm yet to be convinced it's "great"