I think there's a positive knock-on effect in a lot of "I stopped eating X and everything got better" stories that usually go unsaid - once you decide to cut something out, it forces you to actually start _paying attention_ to what goes in.
For a lot of us - myself and friends anecdotally included - that's possibly for the first time in a long time, or ever.
And once you start paying attention, opportunities for other positive adjustments open up. Maybe you only intended to cut sugar, but now you realize through your tracking app you've been ridiculously deficient in potassium or way over target on saturated fats.