In physical optics, chromatic aberration is failure: glass bends wavelengths unequally and edges fringe with color. Digital imagery adopted the flaw as vocabulary, offsetting red and blue channels to suggest a stressed lens, a broken signal, a hit landing.
As a reactive effect it works in bursts: a transient splits the channels for a few frames and the frame itself seems struck. Held constantly it reads as cheap music-video filter, so the good version is dosage plus falloff, strong at edges, calm at center.
Its power comes from photographic memory: audiences have seen lenses fail this way, so the effect smuggles physicality into synthetic images.