I think what they mean is a better representation from an Android API, such as UChar32 from utils/AndroidUnicode.h.
I agree that it's not worthwhile trying to port Python to those Android versions that have a single-byte wchar_t definition.
David, I think you are misunderstanding the purpose of HAVE_USABLE_WCHAR_T: It does *not* specify whether wchar_t can be used. Instead, it specifies whether wchar_t can be used as the datatype for Py_UNICODE. Calling it HAVE_A_WCHAR_T_DEFINITION_THAT_IS_SUITABLE_FOR_USE_AS_BASE_TYPE_OF_PY_UNICODE was just a little too tedious :-)