I know we're not supposed to say "I disagree," so I'll try to go about this a bit more cautiously. This line of thinking is, I think, one of the more pervasive misconceptions about composition still today. When considering accessibility options, a lot of people with disabilities are often told, "Just get some dictation software." But this very rarely does what people need it to do, not just because of the editing difficulty, but because the ways we talk (and listen) are often just too different than the ways we write (and read).