Greetings
FLIR is mostly used where procedures requires a Ceiling, and in that case enables you to fly down to 100ft by which point you should visual (in fact the EVS will be automatically switched off.
CAT IIIB CATIIIC relies only on instruments (meaning Guidance), unlike CAT I or NPAs relies on visual clues.
So EVS FLIR will not be used for that purpose, however on the ground to taxy yes
