Right, so the concept in Go is misnamed. It's not Errors are Values, it's Errors Have Normal Control Flow.

Returning errors makes many things more manageable, definitely. But where they really shine, like in the mapping example, isn't possible in Go. Unless I'm mistaken with how go generics work.

(By the way, I'm a huge fan of how error handling works in Rust and other related functional languages. Definitely not advocating for the classic way of doing Exceptions).