Background: Polyphonic voicing
Polyphonic voicing allows you to resolve a number of situations impossible to score properly otherwise:
Notes starting at the same position, but with different lengths. Without polyphonic voicing you get unnecessary amounts of ties.
Figure: Without and with polyphonic voicing
Vocal scoring and similar. Without polyphonic voicing, all notes starting at the same position are considered parts of a chord. With polyphonic voicing you can give each voice a stem direction, you can have individual rest handling for each voice, etc.
Figure: Without and with polyphonic voicing
Complicated piano systems. Without polyphonic voicing, you have to resort to a fixed split note setting to decide which notes go on which clef. With polyphonic voicing, the split point can be “floating”. The program can even automatically put a bass line on the lower clef for you.
Figure: With a split system and with polyphonic voicing