After a few months of flying the line with no instructor, my point of view has, fortunately, changed.
During the line training, the instructors tend to be "more of a royalist than the king" so they tend to respect the task sharing rules as per the manual to the maximum possible extent.
This extent often stops when ground asks to disconnect external power. The manual says that PM unplugs the GPU and PF answers "you may unplug" to ground.
(In practise, 95% of cases even with instructors, the same pilot will both unplug the GPU and answer to the ground crew.)
With normal captains, even instructors but outside of their instructing missing, I find the method much more reasonable and closer to what some people described here. I can now very easily fly manually and most captains will manage most of the FCU as required without having to ask.
I think I will open a new topic to discuss automation dependency.