We are told how modern airliners have every safety feature available and it would be worrying if we thought that, despite these features, it needs a pilot to monitor every single second of a flight
Well I know what some manufacturers claim and some journalists think but yes, somebody does need to be on watch, all the time. Here's one easy example of why: an autopilot won't ring bells to warn you about is a thunderstorm and it certainly won't avoid it.
In addition there's are a whole host of smaller problems that could develop very quickly into big problems if prompt action isn't taken by a pilot, from conflict/potential collision with another aircraft, engine failure, turbulence...........
In short you do need at least one pilot on watch every second maybe not staring steely eyed at the instruments and grasping the controls, but he/she certainly needs to be awake and aware - the days of HAL doing the driving whilst all the crew can legally doze off are still a long way off. I don't find that worrying at all.