Big fan of the Sphere and U2 do amazing things with it but what I saw from Phish was pretty low effort -- it's such a one off canvas you can see when someone has taken the time to make content just for that surface and when it's a bit more cut and paste and trim the edges in Unreal. $2B to build and I guess an sdk to go along with it was considered too much ? Still at $15k/min of external display time as a billboard there is good reason to make sure what you throw at the pixels is as good as you can get.