We have a similar feature on our TDI. When stopped on an incline and keeping the clutch pedal to the floor the vehicle doesn’t roll. You can let go of the brake pedal and use the clutch and accelerator; no need to wish for a third foot to manage the pedal work.
Once the forward motion starts the brake releases. I haven’t toyed with it to see what degree of an angle puts the mechanics in action but it works!
It absolutely takes the anxiety out of waiting at an incline in a vehicle with a manual transmission with someone on my rear bumper.