I actually didn't know that about the game, I just linked to the articled to provide details. Given the time the game was written, I suspect it was to make the music a bit more complicated. Game "Music" at the time could leave something to be desired. I played a lot of games with just a PC Speaker, which means that all of the sounds were mostly just different beeps. However, we also didn't know any better at the time and just enjoyed it for what it was.