The implication in the article was that you could replace 'sort' with 'Unicode::Collate'.
And that seems to be the real problem. sort isn't broken (that's just link baiting), and neither is Unicode::Collate. They just do different things.
The article does say
Fortunately, you don't have to come up with your own algorithm for dictionary sorting, because Perl provides a standard class to do this for you: Unicode::Collate
So despite its title, it doesn't mandate UC to be a universal replacement for sort, but just for one application.