What it does do is improve your metabolism and health, both physical and mental. This can improve lots of your processes. Neglecting exercise is absolutely destructive and restricting calories does not get you those things, in fact it can work against them. Building muscle also helps burn calories and improves insulin response. Obviously, it is not enough on its own without a healthy lifestyle as a whole.
I think focusing on anything solely is detrimental but focusing on exercise as an aspect is good.
- eat a bit less food
- eat food that is higher on the satiety index
- eat food that has less easily absorbed calories/less processed/etc
- build muscle to raise your resting metabolic rate slightly
- sleep well
etc
I think a bit of everything with mostly a focus on less calories will be easier to adopt than just telling people to track calories into perpetuity and feel like they're starving for a good while.
Exercise -- even heavily -- will never compensate a bad diet; that focus we have on exercise as weight control is detrimental.