As many other people commented on similar projects, one of the issues of trying to use voice dictation instead of typing is the lack of real-time visual indication. When we write, we immediately see the text, which helps to keep the thought (especially in longer sentences/paragraphs). But with dictation, it either comes with a delay or only when dictation is over, and it doesn't feel as comfortable as writing. Tangentially, many people "think as they write" and dictation doesn't offer that experience.
I wonder if it changes with time for people who use dictation often.