LilyPond is great, but the writing process for a lot of music involves a lot of playback, so integration with a half-decent playback engine is really useful. On top of that, you can do almost everything in Dorico and Sibelius with keyboard shortcuts, so they are very power-user-friendly (which is what I like about LaTeX).
Plus, as professional software used by people along (mostly not very much) money with it, productivity is key. Lilypond loses badly here.
I can enter 200 or 300 bars in Dorico in the time I could do 20 in Lilypond - and that’s at the rate I could manage when I was using lilypond regularly.
I also think the output is nicer, which also matters here.
