I've recently joined a team writing primarily in Clojure, whose proponents often tout repl-driven programming as a unique benefit to the language.
In a statically typed language (the stronger the better), aided by a good IDE, I don't need to be constantly executing my code against data during development; My editor is constantly validating my code, and when it stops complaining, my code will work. And months later when I or someone else uses that code in another part of the system, they won't need to execute that code to see how it behaves, as the types themselves provide documentation and as-you-code feedback.
In a statically typed language (the stronger the better), aided by a good IDE, I don't need to be constantly executing my code against data during development; My editor is constantly validating my code, and when it stops complaining, my code will work. And months later when I or someone else uses that code in another part of the system, they won't need to execute that code to see how it behaves, as the types themselves provide documentation and as-you-code feedback.