Whats the benefit of this inplace of using bcrypt or py-pgp? I really don understand this trend of piling on abstraction for simple problems. Its basically a hole github project that could be solved in 2 wrapper functions.
Having custom field classes for specific functionality that Just Work (TM) is idiomatic in Django. Be it for input widgets (phone number field and the like) validation and query capabilities (JSONField, JSONBField), 3rd party integrations (S3-backed file storage), if it's stored in the database, sticking it in the ORM just jives with how you use Django.