What would you not get if you don't do
Double-negative questions trigger reflection and motivation through loss aversion.
Loss Aversion is a powerful driver. You may know about the class experiment where people were asked “Would you accept a 50% chance to win $100 if losing would cost you $50?” Most people refused to take the best. The pain of possibly losing $50 was psychologically greater than the pleasure of potentially gaining $100.
The second benefit of this kind of weird double-negative question is the very fact that it's hard to process at first. It takes a moment to disentangle the double-negative in your mind. But through this, the person is put in a 'thinking' mode.
How do we use this question?
Sparingly.
Use it when you really want to help a team member build motivation around a goal they defined. Instead of asking how they would benefit from succeeding, you can opt for the double-negative. They may give you puzzled looks and you may have to ask it agin, but try it out. It's an example of a positive kind of 'disruptor' that coaching is all about:)
Enjoy!