For almost all of computing history, we have interacted with computing devices via keyboard for input and printer, then screen, for output. Computers are logical devices, and require clean, defined logical statements to interact. Thus, we use precise text.
Human interactions, on the other hand, are less precise but much richer. We interact via touch, sound and sight - both the precise written word and visual pictures. For most of human history, the overwhelming majority of people, upwards of 99%, were illiterate.