People are talking about the music because of a couple things

1) Its a throw back piece from one of the "better" days of Square.

2) It has a Nightmare before Christmas "feel" to it, which in case you were not aware is widely popular among'st human beings.

And since we can only do two things at the moment 1) watch the screen as it changes scenes frequently and 2) listen to the music; the main continuous element is the music, its not being chopped up through out the video (unlike the scenes which are not very long to avoid too many spoilers) so we talk about the music.

Simple as that. Plus its just a really good track.