I guess the question is whether Enum should be considered a first class 'native' type that deserves support in argparse, or just a tool among others in the stdlib.

The fact that Enum is implemented as a class, and lives in a module, tends to lead to the second, but the fact that some constants were converted to enums in the stdlib (like in socket) tends to the first.

As a C/C++ developer, I may have a bias towards enums :)