Eins,
I looked at it, and found that although it gets you to press the right button when you see a note written, it doesn't even come close to playing the piano. Perhaps the reason is that the buttons, A B C D E F G, are not piano keys, and I don't relate seeing a staff with a note with a button. I relate a staff with a note to a piano key. I made some mistakes that I know I wouldn't have at the keyboard. If you can memorize the staff, and it sounds like you have, then pushing buttons won't help. Playing the keys on the piano will. Good luck and keep us posted.
Perhaps Bernhard can offer some suggestions about how to learn the keys in an efficient and appropriate manner.
George