Point. Even so, the book indicates that "A Sword of the Cross always takes the form of a sword, though the precise type of sword may change through the ages." Not that you can't change this, but why do so when you can just as easily make a new item that fits better and doesn't result in a "Knight of the Cross" that punches Denarians with holy brass knuckles?
(As an aside, note that Brass Knuckles of the Cross would cost -4 rather than -3, due to their concealability.)