Yeah, it's surprisingly controversial but I agree, your long-term self is usually the rational one. Commitment devices are all about forcing/incentivizing your short-term self to do what your long-term self deems best. Sometimes people are too extreme with that, like intentionally living in near poverty their whole life in order to save as much as humanly possible for retirement, or suffering through a PhD program they hate because they think it will eventually be worth it.

But those are the exceptions. Mostly it's the other way around, as you say. People undermine their own long-term interests with procrastination or impetuousness.