How is the multiple renderers functionality for BoxEditTool supposed to work?

I am not really sure where else to pose questions like this - so I hope its ok to ask it here.
In the BoxEditTool, there is renderers argument which takes a list of rendereres - what is the intended functionality for having multiple renderes here? Could a usecase for that for example be to have 2 linked plots, and have the user draw boxes in the one plot and then the box is automatically also drawn in the second plot? Or is it something else?

Thanks

The live example in the docs sets multiple renderers. It simply means that the tool can act on any/all of the specified glyphs (nothing to do with separate plots).