A question.

Why is the Desktop metaphor is a good metaphor to use for a business oriented GUI? Is there any useful metaphors for other kinds of activity?

I do not understand your question...

metaphor - noun
1. A figure of speech in which a word or phrase that ordinarily designates one thing is used to designate another, thus making an implicit comparison, as in "a sea of troubles" or "All the world's a stage" (Shakespeare).
2. One thing conceived as representing another; a symbol: "Hollywood has always been an irresistible, prefabricated metaphor for the crass, the materialistic, the shallow, and the craven" (Neal Gabler)

Desktop metaphor is an interface metaphor which is a set of unifying concepts used by graphical user interfaces to help users more easily to interact with the computer.

I understand the computer desktop/real desktop metaphor, but I don't quite understand your query regarding whether there are "any useful metaphors for other types of activity," as that's so broad. Did you have something more specific in mind, or was it just intended to be a general query?

Hi NoSuch.. Its actually a general enquiry from a friend of mine.