It was along those lines that I figured that something that consists largely of healthy fats wouldn't pose a health concern. But I guess I wasn't thinking about other approaches to nutrition: it's entirely possible that a different approach would lead to overeating peanut butter, I guess.
USAmericans have a confection confusingly also called "peanut butter" that is high in sugar and salt, sadly most UK supermarkets now only stock the confection and not the nut-butter.
But more to your question: Most folks spread it on fruit, some veggies, or on a sandwich, much thicker than butter or cream cheese. Too little peanut butter makes for a dry sandwich, especially if you aren't eating jelly along with it. Even when you are eating pure nut butter, it is easier to eat a lot of it. It is similar to someone drinking fruit juice or a smoothie (blended fruit only) can consume many calories in a sitting more easily than one would do with whole fruit. The body perceives it a bit differently with less chewing and whatnot.
Peanuts are a slightly easier option to control. There are about 45 peanuts in a serving of peanut butter. That isn't bad at all and seems a lot more filling in the long run and harder to over-do with a bit of self-control.