Unless you have small children for decades on end, the odds are that you will spend around a third of your life in bed. Which means it is well worth thinking about the healthiness and eco-friendliness of something you'll be spending so much time on and in.
When around eight hours of your day is spent in bodily contact with a surface, you want to know that surface isn't awash with chemicals that may well off-gas for some considerable period and cause skin irritations.