My Guess
When you select a preset (5 pc band for instance) holographic 3D images of the players and instruments will be projected on stage, then when you play your board the images will play the instruments, if you have a Saxophone and a Trumpet player then when you play the Sax the Saxophonist image will play, and when you select Trumpet the Saxophonist will refrain from playing while the image of the Trumpet player will start plying the Trumpet.
But then who knows what the future will bring

Bill