I'm sorry, but that argument doesn't fly. Even if she doesn't talk, she still EMOTES like a huge goofball. During her fight with Potimas, she was doing goofy dances every time she gets a solid hit in.
But then, when she's "The White Lady, she's reserved, verbally AND physically. Again for seemingly no reason other than to mislead the audience.
If that's the case, why does having Kumoko in her head make Ariel act like a goofball?