Take Scala collections. These are written using builders and if-else checks of emptiness which are definitely not idiomatic. Authors of the std-lib did them for you so you do not have to. That is not a red flag.
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.