Public face is all about being recognised - the visual styling, language and characteristics of the experience.
Consistency in the public face ensures that participants are able to recognise components (be they interactive, human, physical) that are a part of the experience.
Beyond providing a recognisable identity, public face can be used for marketing the experience.
Develop a brand around your experience - consistent visual styling:
Part of developing the brand involves developing a language for your experience - a particular style of writing & speaking - especially useful for non-visual elements in the experience.