The optparse-applicative package, as well as optparse-simple, has some undesirable behavior by default, and is quite verbose. This package exists to work around those two. For instance: optparse-applicative does not show help on error by default. optparse-applicative does not disambiguate commands. So, if you have a command my-executable foobar, but your user runs my-executable f, optparse-applicative will not disambiguate this by default. For more specific documentation, see the module documentation for Options.Applicative.Helper.