Don't need them when your types are well-documented. Whereas when you pick bad types, you have to do things like remember to copy-paste that comment explaining what it is, and keep them all up to date. How is that a better solution than just once taking the time to create a descriptive type?
Sorry, I don't copy paste and I don't create a bunch of types until code becomes complex enough to warrant it. And also writing comments is a more involved and important process than just copy pasting them around.
