I agree with all on this one.
To add a little more, I feel that the book studies / knowledge should be done "Hand-In-Hand" with the work experience in the field, in order for the person to grasp everything correctly. In other words, when a person is on the job and runs across something that is either of interest to them, or needs a better explanation than another worker can give, study that subject in depth. Same goes for codes sections.
On the other hand, it is not too practical to study Electrical Engineering stuff and attempt to apply this to daily trade related installations, as there is no relavence here
I think it is very beneficial for an Electrical worker - either at the beginning level, or advanced - to be able to understand how current flows [just some basic circuitry]. Basic values related to this are helpful too.
I also am pleased to hear [and see - in forums] a person ask as many questions as they can, further adding to the knowledge base. This [IMHO] should walk hand-in-hand with actual trade experience.
To sum it up, the knowledge from studies - either self studies, or class room studies - should be "equal" with the in the field trade experience, in order for the two areas to be useful. Only after becoming very fluent in the area of the trade that the person is in should that person extend the knowledge base into studies of topics beond the normal installation of equipment [such as advanced theories, Engineering, Electronics - advanced circuitry and physics, and extended code subjects].
Just my opinion here, mainly from personal experiences with not only myself, but others.