I'd argue its far better to say something like, "Good question. I need to think about that for a minute" rather than just sit there saying nothing at all after being asked something. I know a few engineers who do that and while their answer is normally fine, the awkward silence makes me and others question their social skills. Not their intelligence.
I know other engineers who do the same thing but say, "Let me think about that for a minute" and I've never heard of anyone questioning their ability to think quickly or social skills.
What you are suggesting is not wrong, its just a bit.. rude? awkward? Why impose that feeling on others when a clarifying sentence can prevent it?