My view is that people in advertising/fashion, looking for photographers, have always known where to find them without reference to any books or catalogues... It's a relatively tight wee world, small and utterly incestuous.
I appeared on it for few seasons, ( my agents were paying for it) and I was also awarded a few times for some Fashion commercial work, which my agent submitted.
I do not know if I ever got some jobs out of it, but fair to be said, some old clients that lost track of me were able to find me throug le book. Today the may likely use google instead and my web site will pop up on top of the list.
A friend of mine, also fashio photographer, was able to get a client via le book, who offered him a 6 figures contract. That was about 3 years ago.
Today, I do not think le book and other similar catalogues are so relevant, especially at the money they are asking for.