One of the use-cases for positional-only arguments strikes me as being very sensible: def my_format(fmt, *args, **kwargs): ... fmt.format(*

One of the use-cases for positional-only arguments strikes me as being very sensible: def my_format(fmt, *args, **kwargs): ... fmt.format(*args, **kwargs) suffers from a bug if you want to pass fmt as a keyword argument (e.g. `my_format('{fmt}', fmt='int')`). With positional-only arguments that goes away. You could always force developers into using your code the way you expect by parsing args/kwargs yourself, so it's not like this really changes anything about the "restrictiveness" of the language.