Calories in calories out works you just need to be smart about it and not eat 1600 calories of ice cream bars.
Eating by hunger definitely works but if you've been eating like a pig all your life and your baseline of feeling normal is actually being unhealthy and sedentary, being told to just eat less until you're not hungry just does not work. People have horrible diets and eating habits due to convenience, lack of guidance, and laziness. You do not simply tell someone stop eating so much and you're golden, even if that's true in paper. The reality is that we're humans that make human error all the time.
Tracking calories allows one to realize the proper amount of food they're supposed to intake, without being swayed by appetite and mood. You count the calories and stop when you reach your daily limit.
This is why I suggested before that one shouldn't go on extreme caloric deficits for long (or any length really) periods of time and then binge. It simply isn't sustainable for long periods of time for either physical or mental health. But if you use calorie counting as a tool to defeat appetite and naughty urges, you can start to build a proper understanding of your own body's true nutritional needs and eventually stop counting calories and instead just eat until you're not hungry, and never until you're full (asides on cheat days).
Sustainability aside weight loss all comes down to av calories in being less than maintenance calories, even if some days are much more, yes? ---