It's absolutely awesome. For my use case, it already surpasses latex, but I'm pretty sure that for other usecases there will be a point where latex offers more, at least due to ecosystem support. I for sure made the switch (wrote some personal docs in typst as well), and I'd suggest anybody at least looks into switching, it's so much better :)
From a dev perspective, it's also great that this is useable as a lib, instead of having to muck with an external binary (or rather full external latex installation).
Well, typst provides those means in itself, this crate just makes it easier to fulfill the necessary trait.
I don't really think so. Music notation is also pretty specific, so I'd look into specialized software for that (although it might be theres a latex package, those things are everywhere ^^).