Since all visual effects such as phasers, torpedoes, and tractor beams have to be redone from scratch anyway, it takes just as much effort to make the beam come from the phaser bank or the captain's yacht. Why replicate a known error? The CBS-D team, judging by their results, were loving perfectionists, and they care where it comes from. Otherwise, who's to say the Enterprise can't go to warp in reverse? There's a "bible" for this sort of thing.