It is a form of strong typing because integer could be the length of your toe nail, a temperature or the seconds since the unix epoch.

Sometimes you really want to make sure someone is not going to introduce billion dollar bugs, by making the type different from the underlying representation. In Haskell that would be sth like

     newtype Temperature = Int

At other times, you just want to document in stead of forcing semantics. A contrived example:

    type AgeMin = Int
    type AgeMax = Int

    isAdmissible :: AgeMin -> AgeMax -> Bool   
    isAdmissible :: Int -> Int -> Bool          // less clear