What does sips --man option do

sips, or “scriptable image processing system” is a command-line tool shipping by default with macOS which allows basic image manipulation (think ImageMagick but not as powerful). I found something odd on it’s man page: --man Generate man pages It’s not clear at all why this tool would benefit from a way to generate man pages, nor how the feature works. What does it do and how does one use it?