That does make sense (not quite sure what prompted it, but it makes sense). The rounds human weapons use do not need to be as large as today due to the speed at which they travel, so they could be shaped in a way to make them at least a bit quieter. Energy weapons like those the sovereignty and Rothians use tend to be much quieter than ballistic weapons. Although, since the bullets are not made of glowing balls of energy, they are much more difficult to track back to their source visually. Overall, it would be easier to tell if someone is firing a human weapon in the area, but an energy weapon can more easily give away your exact location.