Purchasing grants you the right to use images of Real Eye in original creations such as baking texture for a game character or rendered Blender images and videos.
Real Eye cannot not be resold or distributed to third parties. Contact for more any more queries.
A procedural shader doesn't require a texture. The 3D software creates it in real time. It is guided by customizable values which the user can change to achieve the look they desire.
Additionally procedural shaders don't have resolution which means they will look crisp and clear no matter how close you get to them.
Of course, Blender make it possible to "bake" a UV mapped texture from a procedural shader if you wish.