Textures from actual photographs (in digital file format such as Bitmap and JPEG) are typically the best to use, sometimes looking exactly like real life surfaces of objects. Shaders and in particular procedural mapping of textures and shaders have come a long way but will likely never have the consistency of the good image texture mapping by an artist one at a time. Humans can detect flaws and inferior appearance, but procedural generation of surfaces will never notice the things which the human mind can. The disadvantage of "live" textures would be that creating many objects or much terrain is much more expensive in labor, time, and cost because each texture must be applied manualy if you want the very best.
On the other hand, I have worked with artists using procedurally generated surfaces which look realistic. Development of these procedures can be time consuming of themselves but worth it for large scenes with many objects or much terrain. Many games use both procedural and manual made surfaces, which allows the best technique for each need.
Get used to coding for both procedural and image applications.