With heavy smoke in the cockpit (other than Marlboro) nobody gives a damn for limitations nor cares about losing his licence. If one manages to set the FMGS to carry out an autoland, then one can just open the window (below 200 kt) and watch the airplane to what it is suposed to do.
It is an option anyone might choose, and would always be legitimate, since we are talking about a critical condition and a captain can depart from regulations for the sake of safety if he deems so.