All protein sources contain the same amount of calories. However that doesn't mean all protein is created equally. We suggest focusing on quality and complete sources of protein for most of your intake. You get more "bang for your buck", where your body can utilize the protein better for things that protein is good for - controlling hunger, repairing muscles, supporting metabolism, etc.
Casein protein is a very high quality protein source, complete in all essential amino acids. It is also a slow digesting protein. In that sense you could say that it's good for weight loss because it can help keep you fuller longer. If it helps with reducing portion sizes elsewhere, then it's definitely a benefit to your weight loss! (along with the other benefits of consuming quality protein).