Earlier quoted context omitted.
scratches. its all about scratches. any poly will scratch pretty easily compared to glass, which is a bad thing when its a lens you are looking through. You could make the argument they could just design an easily replaceable poly lens at a reasonable price, but.....its 2024 device manufacturers hate the idea of any user replaceable parts.
Do you wear glasses or know someone who does? Most of us have plastic lenses with an anti-scratch coating. It works pretty well. What advantage would there be to switch from plastic lenses for practical items like glasses to glass lenses with a thin soft plastic coating?
I legitimately didn't know it was that common; I had to switch to glass lens non-prescription sunglasses a few years ago because even the upper end plastic ones weren't durable enough for me.