You say that while the Katakana evokes the Greek word "Seiren", we should instead use the Greek word's English equivalent "Siren" instead. Well, what's the difference between that and keeping the French "Esmeraude" and "Saphir", the Latin "Rubeus", and the archaic German "Demand" instead of just using all their English equivalents:"Emerald", "Sapphire", "Ruby", and "Diamond"? Why should one foreign word name be ignored and replaced with its English counterpart, but not others?