Exceptions are values in C++, Java, and Python too. They're just values you throw. You can program these values.

As usual, I find that opposition to exceptions is rooted in a misunderstanding of what exceptions really are

Exceptions are values, but normal-value-or-exception (which is what Result<T, E> is) isn’t a value. Review my remarks about map_err, ok_or, &c. with the understanding that Result is handling both branches of the control flow, and you can work with both together, and you might be able to see it a bit more. Try looking at real code bases using these things, with things like heavily method-chained APIs (popular in JS, but exceptions ruin the entire thing, so such APIs in JS tend to just drop errors!). And try to imagine how the collect() forms I described could work, in an exceptions world: it can’t, elegantly; not in the slightest.

Perhaps this also might be clearer: the fuss is not about the errors themselves being values, but about the entire error handling system being just values.