Mediums in general seems to share sets of assumptions, principals of design, but each medium still seems to have a set of assumptions and strategies particular to their qualities of the medium being used.
Are there any aspects of technique unique to charcoal drawing that’s generally leaned on by artists as a somewhat reliable path of connection between an artwork and a viewer?
As an example, as a potter, people are often surprised to hear that texture, balance, and weight are used to trigger arousal and response just as much (possibly more so) than form or function. 
With charcoal drawing, is it the wide range of value that’s available? Is it the softness of the media? All the possibilities of marks that can be made? I’m continually questioning what’s relevant, but so far, I haven’t explored wide enough to know.
Zygote Blum 