Your right there my oniony friend, scratch resistant yes, scratch proof, not yet.
I'd say you were just lucky that day.
Care to take some fine grain sandpaper to the middle of the screen? How about dusting the floor with a bag of sand and then doing a face down skitter across the kitchen floor, say 20 times? Or on that same floor, allow a puppy or two year old to push it around on the sand?
While glass in
most cases, is going to be a 100 times more forgiving than any sort of plastic (coated or not), too much force, friction, pressure, added with the right amount of hardness of the scratching medium, and things will pit, gouge and scratch it. Which is the main reason people with glass top tables, do not use sandpaper on the bottom of their skid proof cups and coasters.
But scratching is not the main worry for glass screened devices, breaking on the other hand is. And while tougher than "normal" tempered glass, Gorilla Glass, sadly is just glass when it comes to edge impacts and being dropped or banged too often. But that won't stop me from buy or owning devices with glass screens.