Disclaiming Banner: I own ATLA in the same way that I own Atlantis.
Distance
When Yangchen was told she was the Avatar, it was with one part surprise and two parts relief that she received the news. She was more skilled in air-bending than her sister nuns, yes, but to be Avatar... The horizon extended in a way she had never known before.
She could go wherever she wanted, how far she wanted; in bending, or in anything. She would never have to answer the questions of her sisters if she would try for enlightenment. Or if she would continue to live as part of the World.