EDIT: Let’s cool it with the downvotes, dudes. We’re not out to cut funding to your black hole detection chamber or revoke the degrees of chiropractors just because a couple of us don’t believe in it, okay? Chill out, participate with the prompt and continue with having a nice day. I’m sure almost everybody has something to add.
What I’ve heard was that it is to build independence for the child, so the parent can leave the child to sleep and do something else. It depends on the age I guess.