Another stupid example of an engineer inventing something so he can justify his job.
While working repair on the assembly line I was talking to an engineer about a part that had been change is such a way that it made it difficult for the operator to install it I asked a Chrysler engineer why changes were made that seemed like they weren't necessary.
What he said was "To stay in the running for Best Engineered Vehicle there must be 50 engineering changes made every model year."
They don't have to be good or useful changes, they just have to be changes.
So essentially changes are made just to try to win awards.
As far as why a twist knob, it's probably so that in the future the computer that's plugged into the grid (skynet, lol) can drive your car and no mechanical input from the driver will be required.