[JohnBooty]

    but it relies on a developer's eyeballs to spot any errors.

I'm assuming a relatively normal/sane environment where code is reviewed at pull request time, and there is a test suite.

    developers not have to expend cycles reasoning about this stuff themselves

It is not my experience that `launch_rocket(distance_km:)` requires any extra cycles whatsoever.

I mean, as a coder, I'm going to have to be cognizant of the type anyway, even if we're doing `launch_rocket(distance:)` in a strongly typed language where `distance` is something of type `RocketLaunchDistance` or whatever.

I'm not arguing against static/strong typing in general or anything. Definitely lots of times when it is the clearly superior choice.