Reading music is pretty much reading and interpreting a language. What can you accomplish if you know how to read music and then interpret it through a musical instrument? Something a little miraculous.
Below are two videos of the same musician sight reading two pieces from Mario games. He's never played the games and never heard the music.
Without practice and without accompaniment he makes Mario music sound good.
I started lessons when I was 8 or so. My parents thought I would benefit from lessons after finding me picking out the tune of Kumbaya on a piano at age 6 by ear or by finding the keys belonging to the notes that I was hearing in my head.
Playing by ear turned out to be a handicap for me as a kid. Why should I learn to read music if I can just play what I hear? So I have only a fundamental understanding of the written language of music. Which means I can never hope to do what this man does so easily.
And...? After all the times I played these games I never realized the songs were rags. I love rags!
Part II of "Solace" from The Sting
I taught myself to play The Entertainer but I wanted to play Scott Joplin and couldn't really read the music - not for the left hand anyway. In order to play songs I hadn't heard before, I had to labouriously label all the notes and memorize where the keys were. I took lessons for accordion not piano and as you know the left hand is all buttons with the chords built in. I wouldn't change many things about my life if I went back but if I did I would pick piano lessons and make myself learn to sight read music like a wizard.