whats the real point in figuring out all the 
we have to in the exam?
If your interest lies in just passing the exam .. fine.
Sometimes, however, out of left field emergencies can arise where the chap with the background might just be able to perform a little better.
I'm sure others can come up with more than a few examples.
One which comes to mind happened quite a while ago. Bird was a Starlifter (as I recall - but the memory may be a little rusty on that point) from one of the Antarctic bases to NZ. Had a problem on departure and ended up with some of the wheel assemblies down. This became a one off on the run planning and implementation exercise.
They finally recovered to NZ - no doubt with a goodly quantity of sweaty palms.
Now, the other category of fellow who just swots for the exams, passes, forgets the little he may have learned along the way .. might be a bit at sea if faced with such a set of circumstances perhaps ?