The chief can collect herbs. It's very handy, actually. It's so much easier to have him go around picking the herbs you need than to take someone off a job.

He can also make potions, so if you're worried about weakening one of your villagers, use the chief and if the potion blows up and weakens him, well, you don't need to worry about making him rest as he doesn't work anyway. Obviously, let him recover before trying again