GPS WAAS is good only down to 200 and 1/2 (200’ above ground cloud base and 1/2 mile visibility underneath)

Cat II ILS can go down to 100 and 1200RVR (100’ bases and 1200’ of runway visual range)

Cat IIIc can go down to 0/0.

200 and 1/2 is perfectly usable for most day to day weather and is certainly good enough for unexpectedly incapacitated pilot.