Forget the DSL part for a second and what this can do is: it can render sheet music, play the corresponding sound and display the same music as a rhythm game.
People writing sheet music with pencil on paper don't need any of that so I'd say this software would be pointless for them. I'd say this leans heavily on hobbyists or beginners, like I said the main use case is my own, and I'm no professional drummer.
This is not a sales pitch, it's just a small project I've been having fun building for myself :)
aiming for more extensions to The New Breed than just Syncopation that you could auto-generate for funny practice/things you wouldnt think of to play?