SG: Shapeshifter Magic
The position here is that shifters don’t use magic. They are magic. They are the real deal, not a magician pretending to be a shape shifter, or a witch temporarily turning herself into cat. Their beast form is as natural to a primal shifter is as their human form. Even for the cursed, abilities that come with their uncontrolled shape-shifting are natural to them. No shapeshifter needs to use magic to gain access to their extraordinary abilities.
Mages able to use magic to turn themselves into things other than human, are still human nonetheless. A shifter is something quite different.