Translating things between languages is probably one of the least interesting capabilities of LLMs - it's the one thing that they're pretty much meant to do well by design.

Surely you agree that directly copying existing code into a different language is still plagiarism?

I completely agree that "reweite this existing codebase into a new language" could be a very powerful tool. But the article is making much bolder claims. And the result was more limited in capability, so you can't even really claim they've achieved the rewrite skill yet.