Both of those statements are wrong. It provides benefits to the user and it's no more of a security vulnerability than having any other networking protocol is.
If anything, v4 is more of a vulnerability because it's so easy to scan and because NAT increases the complexity enough that most people don't understand how their networks work.
If anything, v4 is more of a vulnerability because it's so easy to scan and because NAT increases the complexity enough that most people don't understand how their networks work.