Almost every e-keyboard has a tiny magic button on it; once you press the button, the instrument will play music automatically. Back into practice room age, it would be such a enjoyment for a newbee learning to play the e-keyboard.
Not to exaggerate, demo songs of e-keyboard are good tool for manufacture to 'fraud' someone into buying their products, as demo songs are usually a set of music pieces designed by engineers from factories, and in demo songs you will hear the best tunes and performance from this instrument, although you have to admit the fact that you can NEVER achieve the same effect by playing it by your HANDS. The biggest daydream during playing keyboard would be 'play as amazing as demos did'.
Even if I underrate demos from e-keyboards, I must admit that demo songs do have some certain aesthetic value and we should not ignore that. Like, there's something to say about instrumenting and tricks of arrangement of demos. From the perspective of electronic instruments development, history of demos is kind of history of e-keyboards; you can hear how YAMAHA's sound generating technology comes from FM, DASS to today's AWM and supernatural, and CASIO's CD to HL and HAL. I'm confident to say that you can hear and feel the time changing happening on this tiny mysterious circuit. More than that, music style of demos also change and it is a reflection of world music fashion. From this view, you can regard the revolution of e-keyboards and demos as a condensed history book of modern music – you can see the change of age as we grow up, and before we grow.
And that's why we are collecting demos from electronic instruments (keyboards) manufactured since 1980s: we're hoping to represent an audible, active history material of music, which if can inspire you of something, it would be such a charming result.