Multi-joint exercises, sometimes called “compound exercises,” are great for strength and muscle building because those exercises work many muscle areas at once. Single-joint exercises are a great way to supplement these because those target areas that don’t get targeted as much during multi-joint compound exercises. However, other “compound” exercises - which are usually just disparate exercises put together either in a circuit using the same weight or mashed into one movement - aren’t good for maximizing your effort because they are limited by the weakest area involved in the exercises. Because our lower bodies tend to be stronger than our upper bodies, we cannot progress properly if our lower body lifts (deadlift, squat, etc) are limited by how much we can lift during our upper body lifts (bench, overhead press).