Sid,
You could surmise with the same degree of authority that the radalt will only show what you are currently passing above, and not the sheer cliff face or group of buildings 50 feet in front of you. The UK use of QFE, against the more widespread use of QNH, can be a limiting factor in this sort of assessment IMO. Flying on QNH from my experience has created a better overall judgement of height above ground if for no other reason that you are always aware that your baralt is referenced to sea level.
And for night ops my steerable searchlight/landing light would either be extended, or if retracted I would know the exact number of seconds to run it out to the optimum position. Just one of those idiosyncrasies that I built up over the years.
Now for the discussion on whether you should flare at the bottom of an IMC or night auto, or pull pitch and run on.