Peace of mind is not quite the same as what I meant with mental overhead. What I am referring to is that static type systems have far more complex type systems and semantics, which occupy more brain real estate.

And complexity tends to explode because it carries over to the tools. Static languages require far more complex tools to work with.

I did not mean static languages cannot have REPLs but my experience with them have not been great. They seem hamstrung in a way I cannot articulate well.