On the contrary, writing is key to organizing and clarifying one's thoughts. It is an essential part of learning.

"Writing is nature’s way of letting you know how sloppy your thinking is." -- Guindon

People write a lot of stuff that is not for homework. Maybe they should make a measurement of something else they write. I would even say that writing for homework is a special skill in bullshitting that does not (cannot) exist in other forms of writing.