Does everyday use of analogy debase a language?

Common expressions that you'll hear in the United States include, "My bad," and "You're good." It's rather easy to decipher the meaning of these expressions and it is usually clear that the speaker is not speaking of a moral quality or attribute, but something else. Certainly these expressions show that the use of analogy is quite common in our language, even if we do not know that we are doing it unless we are prompted to reflection. Still, is this a sign that our language is in decline? Instead of saying, "My bad," or, "You're good," should we not retain more traditional expressions like, "My mistake, " and "You are fine."