Difference between:

[Vad]

Afterimage is effectively moving from point A to point B at a speed faster than light. You see them at point A, and you see them arrive at point B. You don't see them between that, but they physically moved it, faster than you could see. If you have the tech yourself, then you are able to keep up with that fast of movement to follow them.

Teleporting is the same thing, except there is nothing between point A and B. You are on point A, and with zero movement, are just AT point B. There's no physical travel between them.

Imagine a wall. Afterimage will let you pop around appearing all you want in front of that wall. Teleportation will actually allow you to appear on the other side of this wall. Afterimage can't because you would physically hit the wall in your travel, while teleporting removes the entire travel space.

Another way of looking at it is to hold up a sheet of paper. You can draw a line from A to B, but if you pinch together the paper and stab the pencil through it at points A and B, that's the difference there.

Read the bold print...there is no flaw. There is no god modding. One is more efficient, one isn't. Basic physics.