One contains water, the other doesn't and that single difference changes everything: how a product feels, how rich it is, and which skin it suits.
Our body lotion contains water on purpose. Water makes a product lighter and helps it absorb quickly, so it sinks in fast and feels fresh rather than heavy. It also lets us add water-loving ingredients like hyaluronic acid, which pulls moisture into the skin and holds it there. That's why a lotion is perfect for everyday, on a normal to slightly dry skin.
Our body butter has no water at all, just pure butters and oils. Nothing watered down, which makes it far richer and more nourishing. Exactly what a dry to very dry skin needs.
Neither is "better." They're simply built for different skin, and different needs.