People make progress by discovering and sharing useful ideas. The value of an idea is proportional to the number of people who use it.
Spoken language gave humans a unique capacity for moving an idea from one person’s neurons to another’s. Writing makes it possible for one person to convey an idea to many others. If a document is well written, anyone with a copy can read it and convert the codified knowledge stored in text back into human capital stored in neurons.Writing is the bottleneck that holds back the rate of diffusion of ideas.
Master writing, speaking, thinking,, to borrow from JBP, and, I should add, getting along with people – and you will become deadly, invincible.