I wonder that myself, even though I prefer black and white photography to color. In today's world, it must seem like an act of craziness when we have the best digital camera's at our disposal that can take beautiful, vibrant color photographs. I was really happy to come across this article by Smashing Magazine: http://www.smashingmagazine.com/2008/06/09/beautiful-black-and-white-photography/
It is one of their inspiration articles, a series they do to inspire artists and designers. The images they included are beautiful, but their explaination of why black and white is not a lost art is well said. This part of the article explained perfectly what I've been struggling to convey to people who ask, "Why black and white?"....
"Compared to colorful designs where catchy colors help the design to stand out, in black-and-white designs the ability to stand out depends only on its ability to communicate rather than on its appealing visual presentation.
Indeed, beautiful black and white photography doesn’t attract with its play of colors. Here close attention to composition, lighting, perspective and the context it is shot in are important. Hence, before considering the photos presented below please prepare some patience and time."
Yes, that's just it. Color can be a crutch too easily relied on for even the best photographers. Take the color away, and see if a photograph can stand on its own. If it can, you've got a truly good photograph. Composition gets lost when color is overwhelming the photographer. I'm guilty, I take thousands of photographs of fall colors, when I should really be looking for that one that stands out. Without color, you are now photographing light, and photography is all about light. So, in answer to the question, I take black and white photographs for thier ability to convey emotion through eliminating the distraction of color, for their testing of my ability to compose a beautiful photograph, and because they show the viewer where the light is. Even if you're not ready to leave out color in your photographs, I hope the article above has inspired you to try it out.