poo is bad but generally it is in the diaper..
Vomit can go anywhere, and happen at the worst time, like int he middle of the night, getting the bed all yuck. So you have to change the sheets in the middle of the night, plus wash their favorite blankie or pillow too.
Plus, kids can possibly choke if they vomit in the middle of the night. I would have said it was highly unlikely until it happened to one of our dearest friends, what a sad way to lose a precious child.