This seems gratuitous to me: Arduino is overdone and this particular implementation does nothing novel. In fact it seems worse than a traditional sticker and felt pen.

How about something new, like using the same hardware to effect an opening/closing hours sign for a small shop whose owner could update it remotely if running late? Or a dynamic version of the advertisement placards in casual restaurants? Why not an assistive device for mute people?

Making an excuse to literally pin Arduino to your body to show to other people like you is not very interesting.