Because she was fucking great.
There are other recordings and films of her performing, though she seems very sure of herself and her voice sounds particularly rich. And I love her hands. There's a performance in black and white version that has embedding disabled where her voice is also amazingly expressive. And the women in the audience---I think I must get a similar expression on my face when I listen.
She is awkward and lovely, and her voice is wonderful and terrible.
So raise a glass, my melancholy friends: To love lost and to love found.