"여자는 매력이 있습니다."
Translation:A woman is charming.
Since it uses the topic marker (는), it's more likely a general statement about each and every woman.
Which is why the site accepts both "A woman is charming." and "Women are charming."
If you were making a sentence about a specific woman, it would be more common to use the subject marker (이/가).
In this case, that would be "여자가 매력이 있습니다."
I agree that it should be accepted. In the future, if the site marks you wrong, the simplest way is to click on the "report" option and select that your answer should've been accepted. It'll also have a section at the bottom where you can explain in detail.
That said, there's not too many mods so it can take some time for the change to get made.
매력 means "charm, (sex) appeal, attraction, magnetism", so attractive and charming are both absolutely correct translations, despite meaning different things in English.
I don't think you can confidently say that unless you are a native Korean speaker. While I'm not Korean, I am Chinese, and 매력 comes from the Hanja 魅力, which means "charm" and is quite distinct from "attractiveness." I assume this remains the case in Korean, especially as the answer is not already accepted. Hope this was helpful.
Is there a reason why this sentence is structured this way, 여자는 매력이 있습니다. but I've also seen "a man is charming" translated as 남자는 매력있습니다 without the delineation between the adjective and the verb? Are the interchangeable? It's possible I had a typo on another version of this question but there was a time when I typed in the latter version of the answer and got told the correct solution was the former (barring the difference between man/woman, I know I got that part right).
Korean is a fairly "high context" language. Particles/Subjects/etc are dropped regularly, especially when spoken. It's almost like anything that could be dropped, with the sentence still making sense, will be dropped.
Like in English, there's a clear difference in grammar between asking "What are you doing?" and "What is he doing?", but in Korean they would likely both be the same with no reference to "you" or "he".