Phoenix Heavenly Body
The mind often took on characteristics of one's Visualization Technique. In fact, some who followed the Mental Realm discipline even believed that one's personality could be changed depending on the technique they chose.
While the [Immortal Sakura] was, of course, an outstanding defensive technique. It could also be used as a Visualization Technique as well. In fact, any Mental Realm technique that relied on some sort of Visualization could be used in this way.
Ryu didn't need to think much to choose this path. Not only would he be able to cultivate his Mental Realm, as he did so, his comprehension of the [Immortal Sakura] technique would deepen. In addition, as time passed, his mind would gain inherently strong defenses due to the constant Visualization.