"Wait a second. I thought you were the one who said "usefulness" is a positive attribute for science - one that would make ID a scientifically acceptable idea. What could be more useful than intelligent design? More importantly, what kind of science can happen without it?"
Actually Issac Assimov said it but I agree with it. Usefulness of an assumption in science lies in its ability to predict verifiable facts not predicted without the assumption.
Intelligent design predicts and assumes organized matter performing specific functions. I reckon we could call it a coincidence of nature that atoms do not fly apart and we have an intelligible universe to explore with our intelligence, but that wouldn't be particularly scientific, would it?