There are good photos of a lot of coasters at
www.joyrides.com.
The only possible thing that I can think of is that the slower disengagement from the chain means less wear on the chain dogs. SOB would be a good example of wear on the chain dogs. Ever hear the sound they make when the train crests the lift? That's the chain dogs skipping over the train as it begins to move faster than the train.
Other than that, I can't imagine any other reason for it.
-------------
Jeff
Webmaster/Admin - CoasterBuzz.com