That's true, but the fact that it wasn't easy created a huge industry of fake information regarding alternative explanations of weight loss from CICO. It's nice to have some more obvious evidence to convince people that no, your body can't magically move and exercise for free when you eat less, among other strange claims I've heard from people struggling to lose weight. People stuck in that rut of not being able to eat less were prone to being deceived by countless weight loss products when the real solution (also hard mind you, but at least more viable) would have been to focus on which activities and diets actually allowed them personally to maintain a calorie deficit.

And as a bonus, now they also have one. A lot of people didn't even believe that was the solution though, and the belief change is important.