White on black can create a very difficulty reading experience. It may increase the contrast, but that's not the only factor in readability.

I personally prefer light text on dark background, but never white on black. Silver an a dark blue works great for me. But font and font weight are also factors.

Because of all those factors, black text on white background is more forgiving and more broadly expected. Which is why my websites are black on white but my vim color scheme is "darkblue".