That's the point.
She's creating a different identity for herself that is separated from her normal voice.
It's like how Bruce Wayne changes his tone when he is Batman.
Or how you talk to your boys compared to how you talk to your mom.
Think of it as a flair for dramatics. To make you feel larger than life. "I'm a Beast"
Besides, her Fallen Angel voice is amazing in general.
I can't tell you how many fangirls she has now after using that voice.
