Benefits of Medial deltoid action - Other

The medial deltoid is the three heads of the shoulder's deltoid muscle. Medial deltoid action is to do abduct the arm, which involves raising the arm out to the side and away from the body. The lateral lift, lateral shoulder raise, and lateral arm rotation are only a few shoulder exercises that require this action. Enhancing shoulder stability and increasing total upper body strength are both aided by medial deltoid muscle development.

https://austerfit.com/blogs/blog/rear-delts-why-they-are-so-important-our-top-3-exercises-to-train-them