True, but I think it shows something simpler than that, too. A complex, spacially accurate map isn’t a tool for communicating; it is a tool for investigating: a model. A schematic map is a tool for communicating, but not investigating. And this distinction goes beyond maps and applies to nearly all ways of communicating.
A pictogram is a good way to communicate: this way to the exit. A painting is a good way to investigate someone else’s perspective on something. Chief’s standing orders are a good way to communicate what his expectations are. A poem is an invitation to investigate part of someone’s internal world. The fuel oil system is best to investigate with own hands and eyes, but photographs aren’t much good if you want to tell someone else how it works: better to draw a schematic diagram if you want to communicate about it.