What is better for performance? Parallax mapping or nanite mesh with a lot of polys?

Just a related-question: the parallax decals would be for things like divots/dents or small additions like sand, or the edges of a bullet-hole? Stuff that would ideally deform geometry in real-life but b/c it’s so small in the game-world, you can get away with doing it as a parallax-decal?