I have used it for years, and I don't think you are missing anything.

With it, you can download music and edit it. You can add lyrics and edit them.

"You can compose your own. All for about $40 - 50, compared to hundreds for other programs.

You do have a MIDI piano keyboard, don't you? You'll need that.

There's one thing it can't do, but I believe there's no program that can do it. No program can 'listen' to you play a tune and then produce the notes for what you just played. That's because computers are too sensitive and they detect every subtle variation of timing. Then they produce a bunch of crazy-looking tied notes and little rests that nobody can figure out.
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I'm sure of this. If you wait for the 'perfect program,' you will waste valuable time that could go into making music instead. "


Sibelius can do this, and do it very well too.