Checked exceptions are a hassle. They don't mix well with other types, they don't generalize well.

Unchecked exceptions are well, unchecked. Allowing unchecked things would completely compromise the Rust safety for no gain at all.

But well, I'm not sure what you are complaining about. The examples where the error is not treated at the point it happens look quite similar to what a try-catch would look. What code do you think error handling gets in the way of the "normal" path?