I haven't messed with one in about six months, here's some notes from then.
The worst part is you can't attach a lens filter, idk maybe you can but it wouldn't be easy. If you fly a single prop plane it's nice to have an ND filter to blur the prop.
It is two cameras, two memory cards also. Only one battery though
So to answer your question yes each card will have 180 video from each camera.
If you do 5.2K H.265 you'll need a $5,000 computer (minimums) to edit on. If you do 5.2K H.264 it's not much worse than editing 4K video. I don't have experience with the mobile phone editing app, it sounds pretty bad.
The datalogger is sucky. If you want the data, you'll be stringing multiple CSV files together to make one file. GoPro doesn't mention this, or how underdeveloped it is. On top of that, you'll end up using 3rd party software to get the data overlay on your video.
The best thing it has going for itself is that the stitching is perfect. Even objects close to it are seamless. That and image stabilization is unparalleled. Battery life isn't bad. You'll need special cables for ICS audio. A GoPro clip mount is a great way to mount it.
Not many people watch 360 video,
and that's okay. You can post a flat 16:9 video from the 360 footage that looks great, with the option to show whatever angle you want.
I took one for a couple of flights, it was fun. I used racerender to overlay the data-logger data after the painstaking task of compiling it. I borrowed it from a friend. As much fun as it was, I'm glad it was borrowed. 1 GoPro with ICS audio has always been enough for me.