Adding a progress indicator is often surprisingly non-trivial. Lets say, you want to copy all files from one directory to the other. Just iterate over the entries and be done. If you want a progress indicator you suddenly need to calculate a list of tasks ahead of time. This gets trickier yet, if those tasks are more heterogeneous, never mind if tasks can have conditional follow-up tasks. Adding any kind of progress bar, jerky or not, is likely to involve major refactoring in all but the simplest cases.