If you're someone that lives on that serialisation boundary between binary data and text data, there are a lot of things about the Python 3 model that really suck. We swung the wrecking ball, but we're still in the process of building the replacements because we don't necessarily know what they should be.
There are three big areas where the distinction is blurry:
When you see the complaints from folks like Armin Ronacher and Chris McDonough about the text model in Python 3, they're not wrong for the kind of code they're writing.
As cross-platform web framework developers they're constantly playing in the binary/text interface layer where most Python programmers don't spend their time. Be grateful to them, folks - just as the web framework developers directly inspired most of the default behaviours in the Python 3 text model, they're suffering through the pain of figuring out how to make the new model work for the use cases that we deliberately broke.