There's no reason why my editor would see I'm using Pandoc in a back and forth exchange if we use a decent DOCX template. Furthermore, DOCX is an open format, and I don't have the luxury of a Windows or Mac machine plus an Office license.
In fact, all documents I typeset with Pandoc -> DOCX look like really carefully typeset documents on Word because the style is so consistent and in line with what latest versions of Word encourage: separation of content and presentation.