From the point of view of an end user, I remember versioning on the Vax using EDT when I spent hours on end entering data from our local emergency department in quite large text files. Over the years, every now and then I have been looking for this functionality on Windows.

Dropbox and OneDrive do this nowadays, in that I can just right click a file and see the different versions and change to a previous one. I work with long documents I write, and this functionality has saved the day a few times.