Consider the example of Sam Abell, who, for all those years shooting color NatGeo spreads since the 1960's, was also shooting his own B&W work quietly and in parallel for year after year after year, never showing it until recently.
Heck, if a potential customer knew the wedding shooter (or commercial shooter) they were considering could be shown an example of his work in a "fine art" magazine like B&W... that might drive sales far more substantial than what collector markets could drive alone. Does Alec Soth's work invalidate itself because he shoots for W or Paris Vogue or whatever? I doubt it. Taryn Simon? Mark Leong? Nope and nope.... Avedon or Arbus? Do we readily dismiss Steichen because he produced (the first) cardboard-stock photo books for babies?
Bjorke, I'm confused with your addressing this point to me. We share the same POV on this but I'm not sure if you realize that.