Ah, it's related to ihb's post.

No, not directly. ihb's post is about avoiding using ampersand without parens to call subroutines except for "advanced purposes" (if you don't know what those are, then you shouldn't be doing them). Using ampersand with parens is great for bypassing prototypes and/or for ensuring you call a user-defined function even if there might be a built-in function by the same name.