New way to learn music or composing something new.
Drag and drop notes/chords kind elements and listen them at same time.
You can also loop and slow down songs.
You don't need any instrument to transcript music, you hear result immediately. Transcript when your are on the bus, on the train etc.
And you can generate music notes from your input.
Note that app does NOT have any automation, it is all on you.
It is also a good way to practice your musical ear.