Deep scratches are one major concern/gripe I have with glass cooktops, hence why my skillet goes nowhere near it. Scratches can introduce weak points that can nucleate a fracture.

https://glassdoctor.com/blog/why-did-my-glass-top-stove-crack

When dragged across the glass surface, rough pots and pans create micro-scratches. When they accumulate over time, they can weaken the integrity of the glass to the point of cracking.