What’s the point of one-way channels in Go?

A channel can be made read-only to whoever receives it, while the sender still has a two-way channel to which they can write. For example:

func F() <-chan int {
    // Create a regular, two-way channel.
    c := make(chan int)

    go func() {
        defer close(c)

        // Do stuff
        c <- 123
    }()

    // Returning it, implicitly converts it to read-only,
    // as per the function return type.
    return c
}

Whoever calls F(), receives a channel from which they can only read.
This is mostly useful to avoid potential misuse of a channel at compile time.
Because read/write-only channels are distinct types, the compiler can use
its existing type-checking mechanisms to ensure the caller does not try to write
stuff into a channel it has no business writing to.