For what it’s worth, I don’t think “reasoning” and “conveying that reasoning via writing” are quite as siloed as you suggest. Many people write long and complicated sentences in a first draft, but it is the subsequent drafts where that initial block of mental marble is carved and honed into a compelling argument. I believe it is in fact that very act of redrafting — seeing one’s work through the eyes of others — that leads to one’s own greater understanding. Skipping that step with AI limits that potential to whatever ended up in the first draft, and Hemingway’s words apply to far more than fiction.