It's due to how language and entropy work; basically people naturally tend to abbreviate frequently used terms.
Some languages have banned positional arguments, like Obj C, but these do get a reputation for being verbose. And verbosity, past a point, hinders readability.
My inclination is that for unary and binary functions, positional arguments should be sugar for the keyword arguments, and anything beyond that must be keywords.
An alternative rule could be you're allowed to designate one positional argument.
Keep in mind, also, that I'll bet there's code in keyword-only languages that just uses single letters for all the keywords. Some people just won't or can't write readable code.
Some languages have banned positional arguments, like Obj C, but these do get a reputation for being verbose. And verbosity, past a point, hinders readability.
My inclination is that for unary and binary functions, positional arguments should be sugar for the keyword arguments, and anything beyond that must be keywords.
An alternative rule could be you're allowed to designate one positional argument.
Keep in mind, also, that I'll bet there's code in keyword-only languages that just uses single letters for all the keywords. Some people just won't or can't write readable code.