If you are not ready for this yet, you will be at some time - when you have felt the horror of loosing days if not weeks of work. But versioning is useful for less dramatic purposes as well, not only for backup. For instance, to help you understand why in the past you made certain changes, why you did a certain analysis in the way you did it. Or you simply want to undo a change in your analysis. Or because you want to keep an audit trail of your analysis. Or to share it with others.
Versioning is different from backing-up
Versioning is not the same as backup. Of course, you are backing up your files, regularly (which means: daily at least). On a Mac, you probably use Time Machine, on Windows a similar product. And of course, the backup is made to a drive that is different from your hard drive. If possible, you hold all your critical files on Dropbox, Box, or other cloud services so that you have a copy of all your critical files, up-to-date, even if your house gets flooded or burns down.