It gives you the dark black color without having to add tint to make it really black.
Annie Sloan's Graphite is a dark gray, almost black. Which is fine if you want to finish with a dark wax to get the darker color and a little color variation in your finish. I finished a maple cabinet in my kitchen with Graphite and dark wax and you can check it out here. I really like the finish on this piece but it does require a little more elbow grease.
With the Wrought Iron I am able to use clear wax.
Neither are wrong. Both give a great look.
Because I used a flash in these pictures the light has bounced off the surface giving it an ashy appearance. In person these color variations do not exist.
I was hesitant to use these photos because of the light reflection and it does make it a little unattractive but oh well, Here they are.