This is fantastic for one reason it ACTUALLY tries to get people to just have fun and try to enjoy the music while also getting people interested in it.
But you could go a step further maybe have way for people to record there own performances and share it with other people who are playing the same game it both grows a community and gets people to try and play some music themselves, hell why stop at the piano you could do this with other instruments as well the skies the limit here.
Also having a sense of humour was also a great selling point awesome little game wish there was more though.