To quote Andrew Lewis, "If you are not paying for it, you're not the customer; you're the product."

You'll know when a user of a Dopamine-backed app installs Space, and that's useful to you. Measuring people trying to give up an addiction feeds back in to understanding the causes of addiction, and in your case presumably gives you quantifiable information you can use to make Dopamine more effective. Saying you made it and give it away out of the goodness of your heart seems a little underhanded.