It's meant to be a phrase that will draw more information about the job; it's not a compliment. Instead you could say something like "I don't know much about t

It's meant to be a phrase that will draw more information about the job; it's not a compliment. Instead you could say something like "I don't know much about that line of work, what sort of challenges do you face?", and I think you'd get the same results. His phrase gets the same response while using less words. This and other statements only work when he is actually listening and genuinely interested.