The problem isn't that there's no implicit conversion between bytes and unicode anymore. The problem is that almost no code beyond the lowest level interfaces is correctly handling it when you need to use bytes. In this case, filepaths (which are bytes in posix, and no using LOCALE is not good enough) don't work. Other examples of things that are bytes:

- Command line arguments

- Environment variables

- stdin/stdout/stderr

- Files in general

- Many expected-to-be-human-readable fields of popular network protocols

In short, there are many situations where you want to treat a bytestring as a string, not as an array of integers.

If bytes in python 3 had acted like str in python 2 (except for the implicit conversions / comparisons with unicode strings), the situation would be a lot better. As it is, they feel like a second-class citizen designed to discourage use, and as a result are unsupported in most libraries that NEED to support them.

(edited for formatting)