The other way around: non-idiomatic use of a language in its standard library points to weaknesses in the language.
If emptiness is something that is so important you add extra branchpoints inside collections to check for it, there ought to be some way of disallowing emptiness or {nil,null}ness in the language itself.
Sure, it is nice for people who use the standard library, but it points to things in the language that perhaps should have been given some more thought.
I'm not sure I would call it a weakness. Performance vs expressiveness and maintainability will always be a trade off. It could be a weakness, but it's just as likely that it was a deliberate trade off.
If emptiness is something that is so important you add extra branchpoints inside collections to check for it, there ought to be some way of disallowing emptiness or {nil,null}ness in the language itself.
Sure, it is nice for people who use the standard library, but it points to things in the language that perhaps should have been given some more thought.