Why we don't use glassware? It's perfect for food. 1. Easy for cleaning 2. Good glass container will look new for years with proper washing 3. It breaks. So it requires full attention of person handling it. We all want to live in present moment, don't we? Use glassware and you will be in the present moment more often ;)
Glass gets very hot in the microwave. Hot enough to burn skin.
So does plastic.
Also, it's a microwave oven. Who thinks that you can stick your hands on something in a device called an "oven" and not get burned?