Most of the appeal is the music's aural impact. Patrons attend to hear an orchestra. Players move from one place to another around the audience, allowing audience members to experience different mixes of the arrangements. Musicians remain stationary on stage. Music is memorized.
Music is read off of a stand.
Communication between musicians and audience members is important. No communication is necessary between musicians and audience. Leader faces audience. Conductor faces orchestra, his back to audience. The show is only part of what the audience is there for.