Nice. I'd been looking for that bottom page for a long time. I'd convinced myself that somebody made that on tumblr.
It's written by James Robinson for SEP & OCT 2008 issue of
Superman (1939) #678
and Superman (1939) #679
I actually like his idea about Zatanna. A clause in her contract that prevents her from using her powers in her shows. TBH This actually makes sense. Zatanna never had a secret identity. People would recognize her anywhere so pretending to not have magical powers seems really dumb. Also this gives her a talent that's not based on her magical gifts.
According to me Zatanna should
-Not have a secret identity.
-Be extremely talented in the art of prestidigitation.
If she does use magic on stage let it be a final closing act to cheer up her audience.