....but the Apple Watch uses a special cold forged SS that's up to 80% harder than ordinary steel! And the person saying it even had a posh british accent!!!
"80% harder" ≠ "invulnerable". Not sure why some people don't make this distinction. As for the "posh" british accent, if you were to actually go to britain you would probably notice a lot of people talking just like that, without necessarily being all that posh.
Anyway, anything that is mirror finish is going to show scratches if it's used, especially on a daily basis. The sapphire front crystal is much harder than the steel casing, and that too scratches under the right circumstances, you don't even need anything as hard or harder than the sapphire itself for it to be noticeable.
Watches you wear on your wrist rub constantly against clothes and stuff like that in our surroundings. Debris may be caught in the cloth, or there could be stiff fibers etc, that when mashed up against the casing will leave tiny marks. It's normal, and to be expected. If you ducktape your iphone to your wrist and keep it there for a couple weeks it will look no better.