That assumes that you as a programmer actually use the thing you are building for something else than testing. I've seen many LoB applications that get optimize

That assumes that you as a programmer actually use the thing you are building for something else than testing. I've seen many LoB applications that get optimized by this process for programmer testing instead of normal user workflow. Yesterday's example (the application is desktop thick client for REST web service): (mostly developmen only) UI for manually creating test data is readily available on application's toolbar, while button for reloading form/view state from server has different placement on each form and in some parts of the application is completely absent (obviously, UI programmers restart the thing often enough that they essentially don't need that button).