It came from the tree so we need to save paper to lessen the deforestation. Pencils, wooden table, wooden chair, rubber, instruments are also product of trees.
It helps us to save what we need to remember or do. You can use it for entertainment like origami and arts, money are made up of paper, it gives us information like in the newspaper/magazine/books and more.
It is not eco-friendly for there is the need to cut the tree. When fewer trees there are more disasters awaiting.