A cursory glance shows the output of this project is simply bounding boxes for multiple hands, while the handpose project you mentioned is tuned for a single hand but it provides the key points for fingers and joints. I sense that handpose is probably far more useful for anyone going beyond a prototype.
I'm not the author for either project, but my impression from some tests has been that hand pose is obviously better information, but fickle. There's simply a limitation of how well a camera operating in the visible light range can do (especially if the palm is not facing the camera). If you don't need to match the image to a hand pose, then just tracking the hand position is going to be more accurate for that.
