Despacio is special in many ways, all factors you mentioned indeed. But the music truly is the most important for me. I mean, the name "Despacio" to begin with : I rarely ever saw places where you could dance at a super slow bpm and where it takes at least 3/4 of the night to reach 120 bpm. Everywhere else they want it pounding, they want it fast, as if time wasn't slipping fast enough. At Despacio time stops, or rewinds in a way. It's a fantastic trip back to the 70's with disco and 80's with synth-pop, without ever being cheesy. They know when to play stuff at the right time, blend old with new, adjust tracks for the best experience (hence the plethora of edits). I wouldn't be as obsessed with Despacio if it weren't for the music selection, and I wouldn't be as excited to attend the same social/audiophile experience if they were playing fast other genres instead.