The importance of audio and what spatial audio's all about.
Spatial audio is essentially audio that emanates from the appropriate action in the 360 sphere. It's critical to 360 filmmaking because the user is free to look anywhere she wants while watching your film, one of the best tools in a 360 filmmaker's toolset is the ability to cue the viewer with 360-positioned spatial audio and intuitively get them to look in the direction of the action.
We all know how important audio is to filmmaking... you can imagine listening to the soundtrack of a film but it's painful to watch a film without the sound. When I'm editing a film, my first edit is always a "radio cut," in which I'm cutting the soundtrack, letting the visuals fall where they may. I essentially am cutting the film so that a blind person could appreciate it first, and once the soundtrack makes sense, I move on to the visuals.
Since I'm just getting started with 360 filmmaking, right now I'm in pure experimentation mode. Unfortunately the current version 10.4 of Final Cut Pro X doesn't directly support spatial audio, so I'm left to using other tools that integrate into Digital Audio Workstations, or the free Facebook 360 spatial audio workstation (screenshot below). I'll be reporting more on this as I dive deeper into it, and hopefully Apple will add support for 360 audio into FCPX soon.
Here's a 2.5D animated 360 video created by Michael "Lippy" Lipman for TedEd that clearly illustrates how compelling spatial audio can be. Make sure that you watch it on the Youtube Android or iOS app and use headphones to listen.