Not every piece of writing has to be sparkling, original prose. The value of clichés is that they get meaning across without a lot of work by either the writer or the reader.

Whether cliché is itself a cliché might depend on how you define cliché. Its origin is from the French. It's onomatopoeic for the sound made when the matrix is dropped into molten metal to make a stereotype plate. At least that's what AHD4 says.