Communication is definitely key. It’s primary to understanding.
The understanding is so important, but it’s only possible if the things that need to be understood are communicated.
What’s obvious to one person can be obscure to another.
So without communicating, one could end up expecting understanding of something that‘s unknown to someone else, which isn’t really fair, regardless of what it is.
Communication isn’t pointless, it’s kind of the point.
Or, to keep with the metaphor, communication is the key that unlocks the door to understanding and comprehension.