However, I'm going to argue that writing is nonetheless a special case.
I was trained as an architect. Unlike photographers, painters, composers, and coders, pre-architects cannot refine their understanding of architecture by doing it. They are confined to various simulations of architecture: models, drawings, renderings, animations, etc. While the emphasis of my course was heavily skewed towards the visual, I personally found that writing was by far the most valuable of all forms of simulation.
The reason is that writing has a unique ability to conjure worlds beyond itself. When I do a 2-point perspective drawing, your brain will conjure it into something greater: a three dimensional space. So far, so good. But can you tell me what the air feels like in that space? Is it perfectly still, or moving through a breezeway? Is it dry or humid? Cool or hot against your skin? Does it carry the sound of echoed footsteps, or birdsong, or traffic, or is it completely silent? Does it smell like rain, or concrete, or freshly-cut grass? Do you feel the radiant heat of stones that have been baking in the sun? Or the humid air which has been evaporatively cooled by a fountain or rich foliage? Can you imagine all these things in sequence, as you move through the space? Can you imagine what the space will feel like at night, or in the rain, or when it is completely empty or thronging full of people?
A single drawing can never convey all of this, and there are many things that drawings can never effectively convey at all. But a few paragraphs can easily conjure all this and more. This isn't the magic of writing, specifically: it's the magic of language: a powerful virtual-reality engine that is very likely hardwired into our neurons.
I found that the the pre-architects who wrote about their work -- and took the writing seriously -- were able to engage with their designs in a far richer capacity than the students who focused on the visual representations alone. This convinced me of the unique importance of writing. It is absolutely true that whatever you want to understand, doing it is better than just learning about it. But doing it and writing about it is best of all.
TL;DR: Doing + writing > Doing