In The beauty of goofy diagrams Einenlum explains how a diagram drawn in a more casual style, can support conveying information easier to the audience.

The thing is, I’m more and more convinced that the style of a presentation matters. Even before looking at the content itself, the style puts you in a particular mood.

[...] To me, although they convey the same content, the first one creates a sense of seriousness and gravity. It feels like only clever people can understand it. I’m already a bit tense and I feel like I need to focus. I almost take a deep breath and say to myself “okay, you can do it”. I feel dumb but I feel that with enough curiosity and hard work I can understand the content.

The second one, on the other hand, makes me feel more relaxed and probably more curious. The topic seems easier to grasp and I’m quite confident I can understand it. It doesn’t mean it brings more clarity: the first diagram is actually probably clearer but the content has more chance of reaching my brain with the second one because I’m more open to it.

(via)