Not familiar with the T6 but on others the Throttle Cut is used to move the throttle trim to its lowest position effectively stalling/killing a gas motor.
Throttle Hold switch along with Throttle Hold programming is a Throttle Curve basically FLAT that you setup for your Helicopter.
You have various Idle Curves along with a Throttle Hold curve for various reasons.
The Throttle Cut function is intended to be used for shutting off the engine, or disarming the speed control accordingly. In internal combustion models, the throttle cut feature prevents inadvertently shutting off of the engine when lowering the throttle stick all the way (such as when coming in for a landing). When used in electric-powered applications, it will prevent inadvertent operation of the speed control.