1) They cannot be seen in IMC. D'uh oh!
Utter nonsense. Were your statement true then few Cat3 landings or take-offs would ever happen. It is a pre-requisite in many aircraft, (not all), that the pilots see a minimum number of lights, even in dense fog, when carrying out Cat 3 operations, this is achieved because the lights are of a certain candle power and
can be seen in IMC. A white or red flashing strobe, of considerably more candle power than a runway light, could well be seen for some distance in dense fog.