The blanket coverage, in media around the world, this morning of her at the Bond premiere is massive free exposure and promotion for British film
And British fashion. As pp said, that dress, and the designer's name, are on front pages all over the world today.
I think the hairdo was right for the dress. Hair down would have spoiled the look, and a simple pleat or chignon would have been too plain.
Camilla looked good too. A very pretty dress, which didn't clash with or compete with Kate's.