Centarus, excellent points. The flip side is this: flying a BE1900 for seven legs, 8 block hours, in a 12-hour duty day, in February, in the Great Lakes, with winter Thunderstorms, icing, windshear, and constant turbulence all day long -- with no autopilot, no flight director, and brown-bagging food and water. The result is arriving back at base at 1AM on the last leg, and on short final approach, the First Officer literally falls asleep while hand flying the aircraft on the ILS (I smacked him gently in the arm while yelling, "Wake up!"). This was not an unusual duty day -- this was regional flying in the 1980s and 1990s. Same thing on Metroliners and Jetstreams. Of course, the poverty pay and roach motels were icing on the cake.
So, this is a case where an autopilot and flight director really were needed. Yes, we were s***-hot with instrument-flying skills, but the end objective is to get the plane safely on the ground without bending any metal.
There was the Vulcan crash after the world tour in 1956, and although there were some poor choices made, one wonders whether a flight director would have been useful after that long and challenging flying.