Confusion around the naming and best practise with useSWRImmutable

[ouchxp]

On the official document, I found two claims that seem to contradict each other:

If the resource is immutable, that will never change if we revalidate again, we can disable all kinds of automatic revalidations for it.
Since version 1.0, SWR provides a helper hook useSWRImmutable to mark the resource as immutable:

If a resource is immutable, why does useSWRImmutable still return a mutate function? There should not be a mutate function otherwise that is not really immutable, right?

The other statement seems to indicate a contradicting opinion that useSWRImmutable is simply a shorthand for useSWR without revalidation:

useSWR(key, fetcher, {
revalidateIfStale: false,
revalidateOnFocus: false,
revalidateOnReconnect: false
})

// equivalent to
useSWRImmutable(key, fetcher)

The revalidateIfStale controls if SWR should revalidate when it mounts and there is stale data.
These 2 hooks above do the exact same thing. Once the data is cached, they will never request it again.

In reality, useSWRImmutable can be used to disable auto revalidation, its implementation seems to have nothing to do with immutable resources. One can use it for both mutable and immutable resources. It is implemented only as a shorthand for useSWR without revalidation. I do not see the first claim holds any ground and I feel the naming useSWRImmutable is a bit misleading since it has nothing to do with immutable resources. Anyone can help clarify?