You cant compare line safty caps vs standard caps, Saftey capacitors are an exception, they are different.

Those arnt standard capacitors by the way, they are special line filter capacitors.

In the tube radio world they used regular capacitors on the line and they loved to explode. Nowadays they make a special type of capacitor that is designed to go directly across the AC line.

Ceramics go bad thermally, they have a poor thermal response but thats the property of ceramic capacitors, and smart engineers usually dont use ceramics in critical portions of circuits. Usually in better designed circuitry, integrators and oscillators, or anything circuit that is critical to its operation use film caps.