Why does parented to bone object copy location of tail instead of the head? If you parent any object to the bone in pose mode ALT+P and then clear its origin (ALT+G, ALT+O), object moves to the Tail, which is a bit strange, because Head is the origin of bone's transformation.

Any purpose why is it made that way?
I guess, this is natural behaviour of the bone. A set of two connected bones (parent+child) means that Head of child will copy location of parent's Tail. 

Same thing with other objects.