You've posted repeatedly defending the way it's written. That means you're saying it should be that way.
No. I've posted repeatedly stating the way it's written, and why it's written that way. It is not the same thing.
The power does not prohibit invisible or intangible attacks. And it very much does not prohibit powers that are not obvious until used.
I'm under the presumption that Breath Weapon is exclusively physical attacks (Mental attacks would be better under Incite Emotion and Social attacks...well, okay, some kind of puke-based Breath Weapon I could see, fine). That means that even if your attack is invisible, your target is going to react. If you wave your hands at, exhale really hard, or stare at someone who then recoils in pain/starts melting/is flung across the room, that's pretty noticeable.
Then again, maybe that's why it's -2 refresh instead of -1.
That's the sword. Michael himself is by all indications a totally nonmagical human in the novels, despite the large amount of divine help that he receives.
Michael, sans sword, was able to make a pair of apparently-mundane daggers glow and ward off a room full of vampires. You sure it's just the Sword?
Forthill and Charity even more so. Neither of them ever does anything to indicate any kind of magical ability.
And neither of them really face down supernatural creatures terribly often. The one power they do seem to use a lot, Guide My Hand, may not be big and flashy obvious, but what's happening is clear enough that Father Forthill and Michael recognize that there's a divine hand involved when the former mysteriously breaks down right in front of the Carpenter house when Michael needs to go out smiting, and Harry has noticed it enough that he's literally bet his life on it on more than one occasion.
In either case, it doesn't matter much because in my original post, I said...
this is a setting where, generally speaking, when supernatural power comes out to play, people can tell by looking at it (unless whoever's behind it is doing something to hide it).
I don't make absolute statements if I can avoid it. They're impossible to defend because there is
always an exception and, of course, always the possibility that I've missed something or are just plain wrong.
Faith powers are tricky to nail down anyway. They may or may not be subject to the same standards as other supernatural powers--they're off in their own subsection, for one, and when your powerset's major sponsor is a guy who lists "works in mysterious ways" as part of his MO, one could easily say that counts under "doing something to hide it."
Hold on, that's my line. Do you still disagree with me?
If you're willing to say that the "problems" with Claws can be more or less solved by taking a power that costs no refresh (Human Guise or Human Form), then we can agree on that.