It makes a difference when overtaking a truck for example. In Germany it‘s possible that the right lane flows with about 85km/h whereas the left lane is used by “overtakers” with about 180+km/h.

One of the reasons I like three lane Autobahnen. You have the left lane for the racers. You have the right lane for the trucks. And you have the middle lane to overtake trucks. It all works fine until some beep beep beep beep decides that staying in the middle lane all the time is better cause they cannot be bothered to switch lanes every few kilometers.