We only learned how to do a lot of those things because we gathered and analyzed data to find out how best to do them! "Eat healthy meals" means something completely different today than 10, 20, or 50 years ago. How you exercise matters a lot. Smoking wasn't always considered unhealthy, nor was drinking. These "simple rules" and what they actually mean have been refined quite a bit.
You figure out this stuff by gathering and analyzing data. Whether or not this specific implementation will result in more meaningful actionable steps, I guess we'll see.
True, we conducted science, part of which involved gathering and analysing data, to refine those "simple rules", though I'd say they've been pretty stable for a long time.
Both our unhealthy habits, and the "simple rules" to keep us healthy, have been around for decades. Building devices that give us gigabytes of data won't change anything. Dr Peter Attia makes a compelling argument in his book "Outlive" that science, as it is structured now, has achieved miracles when it comes to injuries and infectious diseases, but has been more or less powerless, for entirely systemic reasons, to do anything about neurodegenerative and cardiovascular diseases or against cancer and diabetes. His book is well worth reading to understand his argument--but the gist of it is that those require lifestyle changes.
Exactly, if they do reach their goal of deploying tens of thousands of these machines allowing everyone to scan their body frequently and cheaply then even if there are limitations to this technology it will still provide a massive amount of longitudinal data about the human body and the impacts of lifestyle, age, pharmaceutical effects, etc.
The person you replied to mentioned diet and exercise, that seems like an area that would benefit directly from this type of scan. Being able to track the effect on body composition in a highly accurate way where we know exactly how much muscle and fat are gained or lost and where that's happening could tell us a lot about not only the effect on the "average person" but for each individual. I'm sure there are many other less obvious things that could be tracked using this technology.