Kids music toys are often just purely toys tap a button, make a sound... But the skill ceiling could be so much higher, offering the ability to learn and express themselves more. Awesome work.
One of my favorite kids music toy is a mini piano where you have to replay one among 5-6 melodies (each melody is 5-10 notes that you have to memorize by ear — no lights involved) to unlock a little happy sound. This toy managed to keep both, dad and kid busy for a while.