> 3. Better type errors. With currying, writing (f 1 2) instead of (f 1 2 3) silently produces a partial application. The compiler happily infers a function type like :s -> :t and moves on. The real error only surfaces later, when that unexpected function value finally clashes with an incompatible type, often far from the actual mistake. With fixed arity, a missing argument is caught right where it happens.

'Putting things' (multi-argument function calls, in this case) 'in-band doesn't make them go away, but it does successfully hide them from your tooling', part 422.

Thanks for sharing, interesting to see that people writing functional languages also experience the same issues in practice. And they give some reasons I didn't think about.