I can think of lots of potential murderous times letting her out would be good. Long as I can wrangle her up in the end!
It's real vague how it all happened. I remember it, but not as myself cause it ain't my memories. But then it's sort of detached. Did you know Illyria comforted Wesley while he was dying? She walked in to find him mortally wounded, and he told her he would accept the lie (of her pretending to be me) before. But then she told him she couldn't help and asked if he'd like her to lie. I remember that clear as day. The more intense the emotion, the more I feel it.