User preference for fixed staff positions
The option is handy for two reasons. First, it may be helpful to have a fixed reference frame for the main range of notes so that the need to consult with the octave numbers is less needed. And for beginners, most of the sheet music they encounter is going to fall in this range. The second reason is that the note range for the traditional notation treble and bass staves is almost exactly the same as the WYSIWYP fixed staff preference. This makes transitioning between the two notations easier. The following figure shows the two ranges: