Here's my take, for whatever it may add to the conversation, on the video that I linked.
I watched the whole thing. For a long time there was this idea that nothing was happening that made much sense. After I while I was starting to pay attention to the musicians themselves; they were engaged. By the time the piece was over, I had gotten it.
The musicians had a seemingly impossible task; not only were they to respond when pointed to, within the parameters of the cue cards and other signals, but they had to do so within the context of what the other musicians had and were doing. In other words, you didn't just play some random notes when the conductor pointed to you; the musicians were trying to work together to create some kind of musical statement.
And in my view, they did. It seemed to me, as I recall from the one time I watched it, that most of the performance was kinda preparatory; the musicians feeling their way forward, trying to get some context. But as some point as the performance headed into the final stages, the musicians seemed to lock into each other; there was a flow, a movement, I felt like I was being taken some place. The musicians had found a context within which to say something together.
That's my take. I was pretty much unimpressed for quite a while; but by the end I kinda caught on to what they were trying to do, and there was a recognition of what they had achieved.
