Scanned Metahumans vs. built from "ground up"

Are there any differences in the metahumans created from scans and the ones created from the editor? I think I know that there is no difference i.e. you can get the exact same result whether using imported scans or just starting in the editor from “scratch”. However, I’m being told that I’m wrong and that there are differences in the textures and that the ones created from scans are somehow more realistic.

Can anyone help clarify?