I think that painting - and particularly creating mixed-media works, definitely benefits from an ability to multi-task. I know that for me, it's a necessity. I am often impatient when I paint, wanting to add the next layer or object but having to wait for it to dry first. So, working on several pieces at once helps me to fill in the waiting time and not break my creative flow.
Last night I noticed, while blotting some paint brushes, that one of my paint rags was full of paint & wonderful colors, so while my pieces were drying, I decided to create some decorative paper backgrounds using just the rag and some bristol. Fun!