Great work is always the outcome of editing. Without an easy way to edit, we're likely to produce lackluster work — simply out of fear that we'll lose something when we update it. As designers, you've likely experienced this when Photoshop crashed or when an older version of Google Docs lost connection. Those moments are painful.
The same could happen with code, but there is an easy way to protect yourself from such issues. We're talking about version control.