Someone else mentioned other translators of other books and said, simply:
It is more likely the translators used the names that would be familiar with their readers.
That's exactly how I view quite a few things in the Book of Mormon, including the names Jesus and Mary, "Christ" and "Jews" - as well as "synagogue".
It even applies to more commonly discussed things that have been considered anachronisms for a long time. "Steel" could have been steel as we know it now - but the original word might have meant nothing more than "the hardest iron we were capable of making, which is extremely hard to make and break" - and when you are pressed for space, according to the wording in the actual book, one word makes more sense than sixteen words and the meaning still is clear to the readers. Steel easily could have been the best choice in the 19th Century to convey the intended meaning.
That happens all the time in translations. Just look at translations of the Bible, especially those that take a translation in English already and change it for modern or younger readers. There are so many examples that I don't worry at all about the words in any translation being "exact". They are approximations in many cases whenever a change from one language to another occurs - or there is a change in audience. The exact words aren't treated as sacred; the important part is the message / meaning the translator reads from the text and then tries to convey. The key objective is putting that meaning and message into words that make sense to the reader.
One of the most fascinating aspects of the Book of Mormon, and the one that I believe is one of the best evidences of some kind of inspired translation / transmission process, is the inclusion of untranslated words. The monetary references aren't part of that, since everyone understands that monetary systems have radically different names from people to people, but there are cases where words are left untranslated - where an obviously foreign word is left in the record. In the Book of Mormon, "adieu" is a wonderful example of that, and I have written in detail about why I love that word choice in a different post. "Elephant" might have meant "elephant" as we know it, but it might have meant "a huge animal with tusks" (like the mammoths that appear in many Native American Indian oral traditions) - but "cureloms and cumoms" might not have had an appropriate counterpart in Joseph's vocabulary (or might have referred to animals that had become extinct by the time of the translation), which would explain why they were left untranslated.
Lest anyone dismiss that idea, we do it all the time when we adopt a word from another language without translating it. English has many examples of this, but they have become such a regular part of our language that many people don't even realize they are untranslated, foreign words. Japanese even uses a distinct alphabet for untranslated foreign words, so the reader immediately understands that the words are not native Japanese words. There are quite a few English words that are now part of Japanese vocabulary, modified in many cases to match the sounds in their language when the English word simply can't be pronounced properly and sometimes shortened for ease of pronunciation. (For example, Japanese has no "v" or "l" sound, so "television" is pronounced "terebi" - and Japanese people are surprised when an American understands everything they say except the only "English" word in the sentence.)
Anyway, vocabulary in the Book of Mormon simply isn't a big deal to me, since it's all so subjective anyway.