I believe this aspect is mis-understood, and I don't think that it's limited to esoteric practices.
Fundamentally, it's related to the mind and nature, I believe.
If this is true, its applicable to any field or endeavor.
Take training for example. Consider this in a professional/corporate environment.
Those who are usually selected to train "new hires" are usually those with the most experience in said vocation.
Why? Because through experience and performance, the trainer has demonstrated that the skills necessary to perform the tasks required of the position have been adequately incorporated into the trainers mind/actions. There is confidence that this individual can serve as a mentor to others.
Once these concepts have been fully digested by the actor/expert, then the communication of these concepts be shared effectively to the "new hire", thus the new role of "trainer".
So now we apply a more "esoteric" point of view to this process of communication and "sharing".
Frankly, a novel idea or concept that we discover, should NOT be discarded to the winds of noise through "sharing".
I, obviously, have been a perpetrator of this action.
This act of sharing is very powerful. Ideas in, ideas out.
Just like any process, object, or idea, there is a consciousness associated.
So to become "adept" with that process, object, or idea, one should spend time with it.
Do not attempt to describe it with others, but experience it and embrace it.
Make it your own.
Love takes on a new whole new dimension here.
So to bring this back to the "mundane", a teacher/trainer is only as good as they are deep in experience and light in communication.
Take time to digest ideas, before sharing.
Just like nature, there is a process.
Race car drivers have said that "slow is smooth, and smooth is fast".
Another anecdote: "you have no time to do it right in the first place, but you have plenty of time to do it again".