The fundamental issue that is hardly addressed in drawing by shape recognition is that it gets the proportion right but fails to teach the inherent "3D" structure of the animal. The litmus test for drawing is to ask someone to draw an animal. If they can, great. Follow up and see if that draw the same thing but now in isometric view or from an arbitrary viewpoint/perspective. Imagine if you have a camera with various…
This guide IMHO serves perfectly as a material to teach children drawing as a recreational activity. There's almost no explanations, only directions. There's no exact proportion either, you choose what look good to you.