Is it interactive; are they controlling them with the music, or is it all pre-programmed and the musicians just have to keep up? The latter isn't that impressive in the AI department.
The musicians are just a prop, they could use playback. It's not so much interesting because of AI (there is none) or the Holograms but because it is completely synthetic. Unlike Gorillaz and similar bands, there is no actual singer backstage, or recording of the singer, the voice track has been assembled with Yamaha's Vocaloid software.
Granted, it's just a step up from auto-tune which is used by pretty much every major "pop" producer since it's introduction, but completely synthesized voice. It's still technologically impressive (although it's still J-Pop, and thus, by definition, crap
)
If you're looking for an interesting case of AI/music combination check out Animusic. You've probably seen that before.
Linky
Those are "actual" virtual instruments, i.e. the program connects the sound synthesizer and the animation, it gets only fed the score, and the sound and video are direct output.
Maybe because i used to play guitar.