Even a poorly drafted non-disclosure agreement is morally coercive on an honest recipient. So go ahead. Pay big legal fees to those Shortland Street lawyers. It won't do you much good if you're dealing with a dishonest recipient. If what you say is true, why should I even bother reading the rest of your practical guide.
Patience is a virtue.
Let's move on. It limits the disclosure of that information. It imposes restrictions upon the recipient's use of that information. Really, that's all there is to it. Try as I may, I can't think of any other purpose that a non-disclosure agreement serves.