Does the Z-Scale affect performance for sprites?

For standard 3d meshes I know that non-uniform scaling (e.g. scale 1.0, 2.0, 1.3) is not the most optimal thing, since uniformly scaled meshes can be batched.

What about Unity sprites? They have a Z-Scale setting. Does it really do nothing or is there something going on behind the scenes, that might argue for adjust all three scale values of a sprite (e.g. scale 2.0, 2.0, 2.0)?