Your article focused mostly on short term benefits of body language. Larger posture will temporarily elevate self-confidence. This is true. It actually goes farther than this however.

Suppose someone has low self-confidence and they make a habit of “faking” the body language of confidence just to fool people around them. If done long enough, this person will succeed in fooling the people around them that they are actually very self-confident. People then, believing that this person is self-confident, begin to treat that person as if they were actually self-confident. As the faker begins to feel this new way of treated by others they begin to change a core belief in their mind. They now think, people treat me like I’m self confident, so I must actually be self-confident. After this belief is solidified, the person never again fakes self-confident body language because they are actually self confident.
http://attraction-body-language-of-men.com/