I built a 3 point ripper a few years ago.
Used it to rip the roots out around some stumps so I could pull the stumps out.
Also used it to open a trench so I could bury the electrical service cable between the house and pole. I still had to did out the dirt by hand but this loosened it up so the digging was easy.
I rarely use it now. If I were to make another one I would make it longer than this one.