I really do love the way these vine charcoal drawings look, and the way the artists use suggestion rather than detail. I've used it before, and its the most terrifying and frustrating thing I've ever drawn with. If you so much as breathe a little too hard you mess up the drawing. Notice how careful they are around it—they never lay a hand on the paper. It must require nerves of steel and learning how to draw with only the most minimal touches until it looks perfect. Then I have no idea how you store them. If you put fixative on it you totally change it in unpredictable ways. And you can't put it in a stack of drawings or in a portfolio—when you pull it out later it'll be all smudged up and parts of it will just be gone.
I suppose it works if you take a good photo and then that becomes the finished piece. Otherwise I think you'd have to frame it and put glass over it, or at least matt it and lay tissue paper over it with a thick matte in between so it doesn't touch the paper. You can't do that with all your drawings unless you have a lot of storage space.
Pencils allow you to totally state everything in clean crisp line, to utterly control everything, and to put in as much detail as you want. You can get something like the loose suggested look of a charcoal drawing in pencil, espcially if you use some nice big chunky leads and do a lot of smudging and erasing. I think I need to mess around with that a little.