It would be cool, but not too practical.
As you are driving steady in auto-mode the light would default to some setting...likely open diff. Basically not much to look at in that case.
You encounter a turn, hit the brakes, turn, throttle, off-throttle, the DCCD lights are flashing back and forth as the car ballances itself through the turn...
...are you seriously going to be looking which light happens to be on, rather than paying attention to the road in the middle of a turn?
...but it would be cool though.
I GOT IT!!!!
It should have a "data logging mode"!!
...as you drive it records the diff settings that could be downloaded and analyzed with other readings ...