@SimonGill - That's fluff text telling you what it is that GETS the subtype. The mechanical effects of the subtype are in the section labeled "A Shapechanger possesses the following traits." Notably: A shapechanger possesses the following traits (unless otherwise noted in a creature's entry).
Proficient with its natural weapons, with simple weapons, and with any weapons mentioned in the creature's description.
Proficient with any armor mentioned in the creature's description, as well as all lighter forms. If no form of armor is mentioned, the shapechanger is not proficient with armor. A sh…