Nice tutorial, but saying the neck is useless is just so wrong. It wouldn't be a joint on the tori if it were useless.

To put it simply, the neck acts similarly to the abs. It allows you to shift your weight forward or back but is located higher up on the body. As a result, this joint controls the weight distribution of every part below it in a very slight way. If even affects rotation in a way I have yet to understand completely.