Tee Em,
Please don't think that hand flying with FDs on should be done to the exclusion of with the FDs off. I my points are in addition to yours, I am simply saying that it isn't pointless and such practice should not be considered as such as per my afore mentioned specific points.
night mission,
In my experience, hand flying, especially during departures, puts a heavy load on the PNF/PM. Everyone's SA is also reduced during hand flying. Flight during approach without flight directors, and more so A/T, really forces the PF to "stay inside" much more than otherwise. ]
I don't wish to appear argumentative. We hand fly often and I can't say that I have noticed significant workload increases or loss of SA as a result. The PM role doesn't change except for twiddling more knobs and switches and the PM needs to remain just as aware with automation on or off.