However, in a statically-typed language, you must satisfy the type checker for everything, which adds development time. In reality, there might be a small percentage of functions in your code base for which errors (either compile-time or run-time) would likely crop up, yet you must pay that cost for 100% of them.

So that's really where the debate comes from.

Dynamically typed languages can get around this problem by generative testing (in Clojure's case) which allow very fine-tuned aspects of your system's requirements to be automatically tested before run-time without writing tests, which offers some of the same confidence as a compiler.