Do you think there are other professions/industries that would benefit from this?
Definitely. Finance professionals, academic researchers, legislators, among many other professionals, encounter similar version control issues. We are currently focused on law because of our domain expertise and because the problem is particularly pronounced in the law.
They're all incredibly capable formats (from a user perspective anyway), with the caveat that they're utter hell to work with in terms of a programming perspective. It's easier to just toss it into a black box parser/serializer and hope that all the text you need in/out comes out properly on the other side.
Actually generating docx or xlsx files (that aren't trivial) that look exactly like another input file (so you have to account for every notable difference in formatting) is a ton of work; most people who have touched webdev will probably at some point have had to format their emails for Outlooks half-assed ancient HTML parser and even there, you at least control what it's going to look like.