Any time anyone works on any file more than once, they could benefit from using revision control software.
Unfortunately, revision control software is generally a step too far out of the comfortable Default zone that 99% of corporate desktop users live in, and it's only going to get worse for home users as people become more and more reluctant to install software themselves - instead relying on in-browser applications and app stores. It took me 5 months to get a VCS at my local megacorp.
So Microsoft, please do a favour for everyone stuck in default-land by building some basic file versioning into Windows 8. You did it for Compressed Folders, so why not have Versioned Folders?