Often photographers use black and white in situations where the light is poor and colours won’t be rendered correctly. I’ve used this technique in the past and found it very effective in low-light conditions. But the best black and white photos should probably be taken in good light and ‘composed’ in black and white to take account of the greater role played by textures and tones.
I put my camera on B&W mode the other day and photographed the whole morning in monochrome. While it’s not an exercise that I would probably repeat (I only got 4 shots that I was happy with!) it was interesting to see that there’s a lot more to B&W photography than I thought!