Hand flying a difficult approach after a 14 hour day is, IMHO, more dangerous then using the automatics to take the strain, as the PNF/PM/whatever you call the radio monkey is working much much harder. The PF should be just as busy whether the automatics are in or not.
The real problem is that as an industry the "regulators" seem to want to be able to extend the maximum allowable working day under the premise that these aeroplanes "fly themselves", then because we're so knackered at the end of the day, use the automatics to help us out, just look at the new EASA proposals! Vicious circle ensues..
Fatigue has the same effects on the human body as alcohol, and I bet if someone dropped you in the flightdeck after 5 pints and told you to land safely, you'd use the autopilot!
