Exercise is not just about energy balance, just like dieting isn't. You commonly write about low carb diets and the influence they have on insulin sensitivity and energy sources (glucose vs. ketones). The same applies for exercise.

I am not supporting the calorie in vs. out game. Exercise influences body composition (increasing muscle mass and decreasing fat mass) which influences energy needs, hormone balance, and blood sugar control.

Happy to send several articles on the topics if you are interested.

Formal exercise is not necessary (any physical activity is effective) but it is a benficial adjunct to good diet and sleep habits for weight loss and sustaining a healthy weight.