Supervision and briefing are obviously an aspects which should be questioned.
also raises the question of students in what EASA describes as complex.
C/S prop complex? C/S stands for constant speed! It's even more simple than fixed pitch!
I think much of today's avionics are much more complex than a C/S propeller could be. And much more likely to lead to less safe flight with distraction and automation, with temptation to fly eyes in all the time. A C/S prop on most engines is pretty well set and forget, and if you somehow forget to set it, it's just loud and wastes gas....