Words can evoke emotions, imagery, understanding, and so much more. Add in some actual artwork as an added bonus.
I see folks like @honeyed who not only write in their journal, but also doodle as part of the journal experience. Which looks cool. Given the private nature of journals and if not for NaJoPoMo, no one would see those doodles. So it stands to reason that the doodles are for solely for @honeyed's enjoyment. Which is a good reminder that sometimes doing something just because it brings joy to no one but ourselves is reason enough to do it.