Was with you until your recommendation for Word for documentation. Something like a wiki or Sphinx would be much more appropriate than a flawed and proprietary one.
The proper tool is whatever the IT department has installed on everyone's computer by default, and failing that, something simple and easily edited (like raw text or markdown).
I think the proper analogy is like editing documentation in PDF. Software that can edit PDFs is expensive and difficult to use, like LaTeX can be (difficult, not expensive, just in terms of time).
