> 1. It's an external API. We *don't control* most of the potentially
> broken code, so saying "just fix the call sites" effectively solves
> nothing and leaves classes like OrderedDict at risk of subtle silent
> corruption whenever they are passed to a 3rd party C extension.

But since that problem has been existing for ages, we're not in a rush
to fix it either, are we?
After all, people do have to fix their code from time to time (or port
it to Python 3). Using the right APIs for the job is part of that.
Pointing to the abstract alternatives in the documentation for concrete
APIs may help people do so.

In the long term, having a clean CPython API with a proper separation of
concerns is a major benefit.