It all depends, giffgaffs own description of what GOOD quality means actually mentions that screen damage is a possibility
These phones are in perfectly usable condition. They’ve lived a good life and they’re fully functional with only some minor wear and tear.
Think of your friend who uses their phone all the time. Someone who might toss their phone in a pocket or handbag with their keys while they’re out and about. They’re not too worried about the odd mark as long as the phone works.
There may be a few scratches on the screen, some pitting around the edges of the phone or scuffing on the back. Nothing major.
These phones are in very good condition. You can at least tell they’re pre-owned. But only if you look closely.
Think of your friend who keeps their phone safely wrapped in a case but isn’t too bothered by the odd light scratch.
A few superficial marks are possible around the edges of the phone. These phones have lived, but it’s been an easy life.