Optimizing a face of the Cube is never free. Some moves reinforce the rest of the model; six of them create a real tension that has to be managed, not ignored. Pick a cell to see which cubelets drive the effect and what to watch when you make the change.
No face of the cube can be optimized in isolation. Every improvement is judged by its effect on the cube as a whole, or it isn't an improvement, just a displacement you haven't found yet. The interdependence rule, Chapter 5
Rows are the face you push. Columns are the face that feels it.
Every one of these is a saving that books cleanly and takes something back somewhere else. The book names the guardrail for each, which is why three of the fifteen optimization patterns exist only to keep the other twelve honest.