I would focus things around a goal, and make clear that the service will help you stick to it over time. The benefit is over time and not immediate, so I think you're point is really valid.
It also depends on the quality of the insight. Maybe you can tell from my email and social media patterns when I'm sleeping, and make recommendations a few moments after you auth.
If we could better understand what we actually enjoy then we could design a lifestyle that maximizes periods of real well-being and enjoyment. Happiness is a loaded word but wouldn't you contend that the modernity, and all the alienation contrived therein with life reduced to private experiences, could be improved for all by an optimization of private experience?