Earlier quoted context omitted.
The worry with glass is that it's dangerous if it breaks. I find stainless steel Bento boxes are excellent if it's not something that needs a tight seal.
Enamel tableware were once popular and still available. Enamel is glass like in its properties and should be as safe as glass (unless lead containing colour pigment is used which should not be the case nowadays).
I had a situation where (and thankfully nobody was hurt) I had cooked a stew and the enameled coating from the pot I was using had popped off a 2cm x 2cm area section into the stew at sometime during the cooking process. We didn't detect it until we had served half the food.