Since this is a post effect it would be nice to have it behave like the max version. IE you can adjust settings and it updates in the VFB without you having to rerender.
Or am I missing the way the whole thing works?
nevermind 
I missed the “Preview” part DIRECTLY above the effects
please delete this thread
You can just press the “Update” button after rendering, and the effect will be updated, without re-rendering the whole scene.
Best regards,
Vlado