BMIxxx
.... the one that replaces ATC GND instructions?
It does NOT replace the GND instructions. The lighting panel operator works in conjunction with GND to assist the aircraft to follow the designated route. The primary source of control is by GND. It might be that the 'greens' come up before you speak to GND, which MAY give you a clue as to what the instructions will be, but they are just that - a clue.
The same system is also used at LGW and SIN as far as I recall.