I understand your reasoning, but this is one of those things where people will use the default, and your choice as designer is whether you'll have the default that makes it harder to get started with, but reduces bugs down the line, or whether you'll make it easier to get started with, but much more buggy.

History has shown that, if you want things to be popular, you should choose the latter, but I think the tide has turned enough that the former could be the right choice now. That's also the reason why we use Typescript instead of JS, so mandatory static typing would definitely fit with the zeitgeist.

Honestly, the boundary is the one place where I wouldn't want to not have types.