They should have made the point about knowing where errors will happen.

The cherry on top is that you always have a place to add context, but it's not the main point.

In the Python example, anything can fail anywhere. Exceptions can be thrown from deep inside libraries inside libraries and there's no good way to write code that exhaustively handles errors ahead of time. Instead you get whack-a-mole at runtime.

In Go, at least you know where things will fail. It's the poor man's impl of error enumeration, but you at least have it. The error that lib.foo() returned might be the dumbest error in the world (it's the string "oops") but you know lib.foo() would error, and that's more information you have ahead of time than in Python.

In Rust or, idk, Elm, you can do something even better and unify all downstream errors into an exhaustive AGDT like RequestError = NetworkError(A | B | C) | StreamError(D | E) | ParseError(F | G) | FooError, where ABCDEFG are themselves downstream error types from underlying libraries/fns that the request function calls.

Now the callsite of `let result = request("example.com")` can have perfect foresight into all failures.