That is fantastic. I hope they can contain pressurized beverages like soda, that would be really good.
Remember paper gallon milk cartons? I wish they would come back too. What the kid says about plastic outweighing plankton in the ocean is true and frightening. That is what is so bad about plastic. When it degrades and finally breaks down into small particles, the smallest creatures at the very foundation of the earth's ecology eat the plastic particles instead of food.
Until a microbe evolves that can use plastic as a carbon source, plastic is literally forever.