Patrick, it's worth using. Even i'd say necessary. Because it brings preheated air to the verry spot where it's needed, just before the port.
As we discovering, thoses batch act a bit like a normal
wood burner, a bit like a gasifier. And preheated air injected right at the port where the turbulent mixing happens, helps burning the volatiles gasses escaping the main burn.
Matthew walker is onto another iteration of the batch box, where it works even more as a gasifier. And as we discover, secondary air is even more important than thought.
I'll post the link later, as i can't access donkey's site.