Every single system is designed to reduce the workload and the mundane... automation is to
help the pilot fly the aircraft...
Any reasonable person would understand the need to provide oversight of the automation, understand the mechanics of the solution, and disco when applicable.
The recent A380 incident in Singapore shows that additional eyes and brains on the FD can reduce the workload, (five on the flight deck), if they know what they are doing.
Really...the ONLY reason...(while the press may have had some fun with that, I am sure that no one has an expectation that 5 on the flight deck was the reason for the outcome)
You only need two to know what they are doing, and one of those to be able to follow commands.