I fail to see how completely automating an aircraft would make flight inherently safer.
In a nutshell: it is to recognize that humans are better at some tasks, while computers are better at other tasks.
(And also conversely, that humans are bad at some tasks, while computers are bad at other tasks.)
Today there is no such recognition or separation of tasks. The (sophisticated) automation we have in the cockpit is designed to
augment a human pilot. But the pilot is still expected to execute all the tasks, albeit with help -- or lets say "protection" -- from the computers.
But the fact that "protections" are needed points to a sub-optimal division of tasks.
Example: with the current model, since pilots are responsible for flying tasks (but are not very reliable), pilots are expected to
actively "monitor" each other and the automation.
Yet humans are really bad at monitoring. We get bored and lose concentration. Play games on our iPhones. Get distraction with conversation. Fall asleep. Think sexy thoughts. Become incapacitated.
An independent, specialized computer can do a much better job at monitoring.
So perhaps, we should let computers fully do what they're good at: e.g., fly from point A to B, completely automated. Take the human factor out. Computers are not tempted to bypass checklists, bust minimums, or take unauthorized shortcuts. They also don't consume alcohol or drugs, fly fatigued, or develop suicidal or homicidal tendencies. (HAL excepted).
Human pilots can then concentrate on decision making, supervising (not monitoring!), and handling emergency or other non-routine situations. Not by flying, but by commanding.