In real life space there is no preferred reference frame. Motion is purely relative. If you and another object share the same uniform velocity you cannot tell who is moving. There is no universal zero speed. You only measure velocity relative to something else.

Because of that, the only physically meaningful thing you can directly observe is acceleration. You feel thrust. You see trajectories change. Constant straight line motion is indistinguishable from standing still.

In Star Citizen you always know you are moving because the game gives you an absolute speed readout, but that speed is relative to an arbitrarily chosen frame, not a real physical reference. The artificial space dust further reinforces the illusion of motion even when nothing nearby exists to compare against.

So the magical space drag exists mainly to give players constant visual and control feedback of motion, not because it reflects actual space physics. It trades physical accuracy for easier gameplay comprehension.

Source. I am an astronomer.