The emperor has no need of a suitcase. Recall the proverb: "Sed la imperiestro ne havas vestojn"
I agree. In "British English", "case" is often used for "suitcase". I was quite surprised when "The emperor flew without a case" was marked as being wrong. I have reported it.
Why not "The emperor flew without a case." ? After all case and suitcase are synonymous, at least in UK English (I had to check with the OED just to make sure that it wasn't a word that I was misusing). Is it not also a synonym in American English? Reported.