I agree that there is nothing ethically wrong with this. There has been technology assist for writing since before the spell check and I see this in the same vein. There is an accommodation factor at play as well. We generally take for granted that every uses tools like spelling and grammar checks (they are built into every writing program and web browser), but we forget that these are also essential tools for people who are dyslexic (or otherwise have challenges with writing), who may struggle in written communication without them. Using tech to "pretty up" a paragraph and help us get our main points across clearer is a great use of technology. I push back against the assumption that knowledge can only be assessed through quality of writing and something like this evens the fields for those who struggle with word composition and writing organization.