It's not a song, it's a prelude. And actually not very technically difficult, one reason for its immediate and enduring popularity. The simultaneous chords are just played very quickly one after the other and not "rolled".
"not very technically difficult" is a matter of perspective. It's about as difficult a piece as any student or amateur is ever going to play or be exposed to and few students or amateurs are skilled enough to play it.
But it is accessible to amateurs, and sounds very impressive. Which is, as you noted, a good reason why it's so popular. It's a good piece to pull out when you want to show off.
