Well, imagine that your code is serializing and deserializing someone else's type. You probably care more in that context about the underlying type and not the

Well, imagine that your code is serializing and deserializing someone else's type. You probably care more in that context about the underlying type and not the newtype, and the newtype doesn't help you. Now, I did say this option was worth it. And there are cases of being too conservative (Golang?). But when designing and programming, one should look at the tradeoff. Abstraction is not always worth its costs [EDIT: and sometimes you can have less costs by a better abstraction, but being aware of the costs helps to think about the better abstraction].