The value of cliché – the use of stock imagery and other familiar elements – is accessibility and mutual understanding. If the Game Master tells you the new campaign is to be set in the “Duchy of Crows” and concerns an evil priest gathering the Hill Ogres to his cause, that may sound a bit threadbare, but it also provides a reliable common ground. Everyone can jump right in and focus on what the game is really about: the PCs and their adventures. If, by contrast, the GM tells you the new campaign takes place in the Shining Tertiary Plane of Tsalvanithra, a science-fantasy blend of Mayan mythology, Depression-era satire, 16th-century French politics and Japanese courtly manners, you’re in for some research before you dare put a mark on the character sheet. The most popular games rely on stock images as a language for skipping to the good parts (and for sharing in a celebration of things gamers enjoy celebrating). Games that make a point of shunning cliché tend to be more niche.
S. John Ross, Five Elements of Commercially Viable RPG Design.