I have a recollection that some very low DH "Cat3B" operations used a DH purely for confirmation of sufficient visibility to control the aircraft laterally after touchdown, in the event of roll-out guidance (either autopilot or with the "barber's pole" glareshield mounted "Para-Visual-display) failure. It was not a DH of the conventional kind requiring assessment of position and rate of change of position. The actual landing had to be automatic. However I can't supply chapter and verse on that.