I think useless might be a stretch. While I certainly prefer compile time checks as well, spec is a huge step forward for folks that are committed to Clojure. I

I think useless might be a stretch. While I certainly prefer compile time checks as well, spec is a huge step forward for folks that are committed to Clojure. If there was no merit to runtime checking, Haskell wouldn't have QuickCheck and would exclusively rely on compile time checking.