What is the point of this switch? Is it simply to eliminate the mechanical spring and lever system?
Like Bill said, it replaces the manual stomp-start floor pedal that actuates the bendix with an electric switch that activates the solenoid, while having the same general appearance of the stomp-start pedal. In my case, my truck is no where near useable but I regularly find myself needing to start the truck while working on it. Every other vehicle I own, I just leave a push button wired to the solenoid and have an easy way to start it. With this truck I have to drop what I'm doing and go get into the cab. Just a three minute annoyance I'd like to eliminate.
It's little things like this that add up to a truck that I hate to work on. But I do like the character, history, and uniqueness of the stomp-start pedal and would like to keep some homage to it around.