I enjoy using markers, sometimes to the chagrin of my illustration teacher. Sure a similar method can be reproduced digitally, but there is no ctrl-z with ink and paper. Its quite nice to throw down shapes and develop something cool while not being tethered to a PC. A small sketchbook and a few prismacolors or copics and…
Prismacolor markers are mega expensive...but you really cant beat them in terms of marker quality. Calling them a waste of time is pretty silly, that's like calling acrylic paint or colored pencils a waste of time. Just because it wont be the tool that you're using 100% of the time at a job doesn't mean you wont learn…