It's the same as Quarks 'dynamic torque settings', or MM punch control....
It's not just a delay, it's a slew delay.. so say you set the delay to .86, if the R/C is sitting still, then you pull full throttle, AS SOON as you pull the trigger it will increase the voltage to the motor in a linear fashion in the 0.86 seconds that you set. So, between 0.00 seconds and 0.86 seconds, the 'throttle', or ultimately, the voltage going to the motor.
These settings are very friendly for your trucks drive train, it drastically reduces the "CAPOW" bang on your tranny gears.. it also feels nice have this delay as well, it makes it feel 'juicy'.