So when you get your "Tea No Biscuits" with the boss for that HARD GPWS warning - that's your defence -- "Saved Five mins and a bit of juice and you knew where the ground was cos you had the EGPWS on and the moon lit the way up a bit !
"and makes safe commercial sense"
Might make bit of commercial sense but would not call it SAFE especially as Jet A1 tells us that this was at night !!!
SO is it legal ??? Me thinks if you check your ops manual regarding Visual approaches at night you need to have reference to the Approach lights and or runway !! No chance at VILNA !