reading over the linked description... it appears to grant an untyped bonus to armor class. i was expecting it to say armor or natural armor, but it simply says bonus, which makes it untyped, yes?
in which case, you could wear bracers of armor and an amulet of natural armor with it, since they do not count as armor, and they should both stack. it seems shields are nixed too, as it lists "any kind of armor". psionics granting insight bonuses to ac should also work.
i suppose that being able to grow scales and shed them pretty much at will (if not exactly in a timely fashion) might be useful in various rp situations where you need to unmistakably appear different without needing magic, psionics, or a disguise check. just be sure to keep a dustpan handy.
