I have always been of the opinion and it was stressed to us during training, know your equipment, its there to help you out.
As long as you understand the kit and its limitations, exercise some caution when prevailing conditions are not suitable, then they are another important and useful tool for us.
I always use the NDB's for SA whether VMC or IMC, as people have said they are useful in approaches for giving you an indication of where you are in the pattern and in thier own right, if a little wobbly sometimes.
Nick