[sjy]

The ability to keep track of many, potentially thousands of individual changes and assign labels to significant versions. Track Changes is basically like Git if every file write triggered an automatic commit with no commit message and anyone could rewrite history at any time. SharePoint major versions are better but they’re not free, standard, portable or popular.

[gamblor956]

If you have a legal agreement with many thousands of changes at any point, someone is getting fired for royally fucking up...

Legal agreements are basically a war over each party's choice of standardized language followed by battles over customized terms.

[sjy]

That may be accurate for commercial contracts but lawyers write lots of other documents too, some of which are subject to thousands of edits. Think about judicial opinions, advices, written arguments, continuously updated legal commentary services, public reports, or indeed statutes. These documents are often carefully drafted over months and complex manual protocols get set up to manage it, due to the limitations of Track Changes and the lack of familiarity with the tools used by software engineers.