When Cat II and III operations are being used officially,i.e. due to WX or system tests,several changes will take place;one is the use of special Cat II&III holding positions to keep other traffic out of the ILS system's area,this may also involve closing taxiways close to the RWY,increased separation between traffic on finals,special reporting procedures,etc.
A heavy reduction in traffic capacity is the result,so these procedures are not in force if there's no need for them.A radio call on finals is way too short time to implement these procedures.
So why this radiocall in good visibility and WX conditions? Beats me!
"Luck and superstition wins all the time"!