Expanding on what a sibling comment said, we live in an adversarial environment. A successful food product is one you want to eat, whether you need it or not.
Willpower is important, I agree. Almost everyone needing willpower to not eat, though, is a fairly new phenomenon. If anything, the new drugs restore the balance that existed before —and if willpower is a limited resource, actively help society by returning to us what is taken by the relentless grind of profit maximization.
For a bit. The grind will not sit still.
Willpower to not eat really isn't the same as willpower to eat reasonably (in quantity and quality), though. There's even exercise to offset the effects of suboptimal alimentation.
Either willpower is fungible, in which case it doesn’t matter what you use it on because you’re using it up no matter what, or it isn’t, in which case the original point about losing willpower due to leaning on GPL-1 inhibitors for weight loss is mostly invalid, since it wouldn’t affect the willpower to do other things.