A rough surface will make it impossible to see through your safety goggles.
Story time: When my little brother was in first grade or so, he'd just gotten a pair of new glasses. The optician had upsold my mom on a scratch-resistant coating. Once it was on the glasses, the optician demonstrated the coating to my mom
and my brother by trying to scratch the glasses with a key. That weekend, my siblings and I were at the park when my little brother decided to send his glasses down the metal "tornado" slide. We warned him they would scratch, but he bragged about how they couldn't.
They did.
When he put them on, there were heavy, dense scratches exactly where his eyeballs were, so that his eyes actually looked all white. It still cracks me up remembering what they looked like (for the half-second before his realization that he couldn't see through them and was about to be in big trouble).
When my mom brought the glasses to the optician for new lenses, the optician tried to charge her. My mom told her she was the idiot for demonstrating scratch-resistance in front of a young child, and the new lenses were free (with an admonition that this was a one-time deal). He'd of course learned his lesson by then!