"I think it is a matter of personal taste. Sometimes colored photos are not as "ARTSY" when it comes to these shots. It's often photographers do this (in my opinion) to show the contours of the body and emphasize on shadows and its form. Colored photos (mostly with the faces of models exposed) look quite a bit distracting and a little similar to porn in most magz (which also depends on the level of perversion anyone gets) so they resort to the obvious one. Yours however is not on that level and afaik is still very good and classy. If I were to try this on black and white I would put a softer texture (since she is an angel) but deep and intense black. I guess it is just a matter of taste. I'm not an expert but this is my opinion hehe!"
Did I justify the real reason why?! I guess so. I think it is quite elementary but we all know how it is to explain something simple these days. It is a wide art form after all. I have done both black and white and colored shots for nude but these days I wouldn't be able to notice simple things like these anymore so when I made this post I think I kinda made sense. That seldom happens LOL! I won't be posting a corresponding photo about this subject because you may see something you don't want to see ha-ha!