What geometry-based feature does the pyramid shape introduce that increases internal capacity over a flat bag?

A vital third dimension

The fundamental superiority of the pyramid, or tetrahedron, shape lies in its geometry compared to the inherently two-dimensional flat tea bag. By introducing a vital third dimension, the pyramid configuration creates a substantially greater internal capacity, even when holding the exact same measure of dry tea material as a flat bag. This increased volume is crucial because it grants the tea leaves the necessary room to move, absorb liquid, and undergo the essential process of unfurling. Without this volumetric space, expansion is severely restricted, leading to inefficient use of the tea mass, a problem the three-dimensional structure is specifically engineered to solve.