That's one of potentially unlimited use cases. iota composes with just about any static math expression to generate almost any kind of sequence. The most common is obviously conveniently constructing bit vectors; which is possible in C, but not as an automatically composed sequence. This really is a nice feature in practice and certainly not the only type of convenient sequence you can create.

A contrived example might be:

    const (
        A rune = 'A' + iota
        B
    )

    func main() {
        fmt.Printf("Hello %c", B)
    }

You can, of course, just write it like a C enum if you were so inclined and that willing to go out of your way to show your disinterest in something.