I don't think this was suggested before but if it did let me know I'd delete it.
Choose who can send you messages:
Everyone – Anyone can message you.
Friends Only – Only people you're friends with can message you.
No One – No one can send you messages
Only few friends : put them in the list
Some people might not want to receive messages from strangers who never interacted with them , or avoid spams, this can be helpful to reduce unwanted messages
