I would like to know the main advantage of using buttermilk as a hydrator and minor source of fat (1% fat, right?) in baking, over using regular milk or cream.
Since it's a byproduct of producing butter, I would suppose that early peoples developed recipes to use buttermilk solely, instead of remixing it with butter like in most recipes I see online -- though this is just a comment rather than a question, feel free to share any insights.
Backstory is I tried whipping my own butter to use in my cookie recipe. The results were absoutely superior (soft, fragrant cookies), since the butter still has some buttermilk left inside. I was able to produce the same yield whilst holding back one egg from the usual recipe.