PDF to Music is overpriced crapware.
That's rather harsh.
Converting music PDFs to MIDI or MusicXML is far more complex than doing the same for ordinary text.
The fact that it's complex and that there are fewer users of it is why it's less developed and why it's costly. If I'd spent three or four years developing and honing such a software I think I'd be pretty annoyed by that.
Fortunately for me, I felt it was too complex and has too small a market to make a worthwhile business, so I never went near it.
This is one area where AI might eventually make a decent improvement.