The main objective would be to have a consistent interface for managing success responses and Error responses.
I find Requests::Response interface cleaner than Net::HTTP error responses (EG, response.to_hash to get the response headers is not very communicative nor intuitive, I almost always need to go back to Net:HTTP docs, which are not very communicative either :P)
I think having this consistency can make client code less surprising and might allow a more fluent dev experience.