I always use a pencil over a pen when ever I can. I write a lot outdoors and pens don't work in the rain. And there's also the story of pens and pencils in space I like.
Sadly, that very entertaining story is certainly apocryphal. Pencils have their own problems. A device that sheds conductive graphite into a weightless environment full of electronics is not necessarily an obvious choice, nor is something made out of dry wood and graphite that needs to be regularly shaved into fine strips for a high-oxygen environment.
Yeah you're absolutely correct its pretty much fake but I still like the story, just like I like the toothpaste factory story. Essentially keep it simple stupid, don't over engineer, and do your research.