It could be an interesting use case for Draw to create a musical score with a few lines (ideally from a template that is added) and notes from the gallery. Would be a limited number of nice looking symbols.
There is a reason that special programs to layout scores exists. Just have a look at the image on the main page of LilyPond: http://lilypond.org/
IMHO: from the complexity, this feature would need something like StarMath to be useful. This is totally out of scope for Draw and definitely nothing, which just needs a Gallery and a Grid. For me that's a WONTFIX.
I'm all for have usefull usecases for draw but I'm also against stuff like this cause I don't see the "selling point / usecase" why LibO draw should be used for stuff like this.
I'm thinking on something that will fit for schools, universities, ... cause this is where we will find our (future) contributors.
Something that will be usefull for this usebase would be a good idea.
I think it is worth noting that the extension writers have already delivered a number of packages for supporting the use cases.
Both simple, ie producing blank sheet music, and integration with two full scoring applications.
I can see utility to a *few* "decorative" music icons in the gallery, e.g. 'dal segno'; the clefs-G,C,F; etc.
Otherwise the "correct" way is to support glyph layout with the Unicode 'Musical Symbols' (1D100-1D1FF) as supplemented by the codepoints from the 'Miscellaneous Symbols' block.
Symboloa has complete coverage, while on Windows Segoe UI Symbol covers a fair bit.
Then there are fully SMuFL complant fonts like Bravura (with standardized PUA mappings needed to support legacy notation systems).
We discussed the idea in the design meeting and decided to not do it. There are better suited tools and the use case is out of scope.