The issue was (and probably still is) that MS Word paginates footnotes improperly. They can't change it because it will break backwards compatibility. This handed the legal market to WP. And because you can't reliably import/export the documents and get pagination to work, you often have legal firms using Word to do the initial preparation and then hand it over to a legal secretary to type the whole thing into WP -- which will be the document that is submitted to the court.