Because I've scoured around, the Ninja's Trump isn't even named "Shinobi no Saigoshuriken" or "ninja taram-pu" in its originating material. It's named Fuma Shuriken in its original kanji, like the huge decapitating and dismembering tossable blender blades that they are usually depicted as in other works regarding ninjas. They could have easily just left the original name there or called it Master's Shuriken or Shinobi's Secret or Ninja's Secret or whatever. But no, don't make references to demons despite the Demon Axe being the ultimate axe weapon and that Fuma literally translates from its kanji to "Wind Demon".So the re-translation screwed up what the weapon even was in the first place, and they could have called them "Ninja Cards" instead. But no, "Ninja Star", because fuck spending two minutes researching why they'd use "Trump" as a name for a weapon. That's not localization, that's just laziness.
I could tell this escapade was going on because Final Fantasy Type-0's ultimate weapons used the word Trump in them before the coming of the so called New Reich.