I find this unconvincing. People who are smart enough to create something of great value will often have valuable input on other things as well. My favorite example is Richard Feynman. No matter what he says, it makes me wiser.

'But Feynman only has expertise in Physics'. Well. A more accurate picture might be: Feynman is a hell of a smart guy, he chose to dedicate most of his time to Physics, but that doesn't make him any less smarter when he talks about other things.