From the homepage's feature list:

""All-in-One" Shader. "Click together" your personal shader:"

But, maybe, you are right, and one can't use DoF separately from others.

CHrisB showed somewhere a single DoF, maybe, it is in the wiki, I don't know.

The main advantage of Shade-C is actually that those shaders work together which is one of the more difficult part in shader programming.