I think the difference is that the try_from implementation can’t be exhaustive because the input value space is much larger than the enum space, so nothing real

I think the difference is that the try_from implementation can’t be exhaustive because the input value space is much larger than the enum space, so nothing really requires you to add the new variant to that impl when you add the variant to the enum. This provides a non-macro solution that forces the two to stay in sync, which is pretty nice if you either don’t like macros or don’t feel comfortable building them yet. I agree with the author it’s also definitely more readable and obvious than a macro, even if the whole approach makes me feel a bit weird at first blush.