What is the benefit of this hot start switch. I am trying to visualize what it does over the conventional starter, but don't quite get it.

I thought the key switch 'start' position energized the solenoid coil (minor current draw), which pulled the plunger forward and closed the large copper 'disc switch' (internal) thus supplying full battery voltage to the starter windings.

How can you improve on this system. What am I not understanding!

Stuart