Digital is like shooting color transparency--not as much latitude as b/w neg, and you have to expose for the highlights instead of the shadows. By the same token, Polaroid wasn't a perfect match for negative film either. You had to calibrate to use it as a reliable proofing tool, and likewise, you would have to calibrate your digital camera to use it as a proofing tool in the studio. You could find, for instance, that a perfect digital exposure gives you a flat neg for traditional enlargement, so you have to think about how to compensate for that.