Obviously the music is foremost and forefront. What can you say? It's flawless and incredible. I think most of us come here for the music.
But I think the mysterious/mystical/occult aspect of the band also drew a ton of people in and is in a way just as important as the music. You had the 70's, no twitter or instagram, no instant updates, all the crazy tour stories had a mythical aspect to them, friends told you they did this or that on tour, or Jimmy or Robert said what???? And it was endless questions with no answer available: Whether it be the Crowley references on the actual record of LZ3, or who the hell is that guy on the cover of Zoso and what does it mean? Why is there that bearded guy with a lantern? Why is Stairway the only song with lyrics printed and who's that guy reading a book in the liner notes? Why did Jimmy have references to astrology on his pants on tour? Did they really backmask the music?
These types of questions and the answers to them are almost irrevalant, part of what made Zeppelin, well, ZEPPELIN was their larger than life characters, the odd Norse mythology lyrics of Robert, the references to Tolkien thrown in, and the occult all played a part. I dont think Zeppelin would be who they are without this aspect of the band. Back in the day you didnt have google to figure out any of it, you'd just lay on your back with headphones listening to LZIV and burn a candle ala Almost Famous pouring over the album art for hours.
The music is the music. Its why they matter. But the mystical aspects of the operation they ran were actually genius.
Did that part of LZ draw you in?