I don't think this a good thing, since I felt it clearly answered the question, whether it was suggesting a duplicate answer or a link pointing else where.
If you think that question is a duplicate of another question, then you should vote to close it as duplicate, if you have the privilege of voting to close questions, or flag it as duplicate of an existing question.
Saying that the question is a duplicate of another question doesn't answer that question; it would be an answer if you report what said in an answer for the other question, and the link to the answer you quoted. If you think the question is a duplicate, you should not quote an answer for the other question in an answer, though.
Let analyze the other links you could be referring to:
The link is for the FAQ where it is reported the question should not be allowed in the site where it is asked: Also in this case, what you wrote as answer is not answering the question; to make a comparison, it would be like answering with "it will start raining" to somebody who asks you "What time is it?" It would probably be an answer if it always starts to rain at the same hour all the days, but as that is not what generally happens, that is not an answer.
The link is for a page where what the question ask is explained: Answers that just contains a link are normally not considered answers; link rot happens, and who reads the answer would not be able to understand what you are suggesting as solution to the problem reported in the question. If the solution is reported in a page you found online, you should report in the answer you write a summary of what reported in that page, and give the link to the page for who wants more details. Clearly, you cannot copy and paste the content of that page, but you can report the main points that allow who reads to understand what the solution is.
An SE site is a Q&A site, where the answer is strictly what answer the question; other "answers" are generally not tolerated, and they will be deleted, or converted in comments.
These are example of "answers" that could be deleted, or converted in comments:
I have the same problem, but I am using a different version of Drupal. May anybody help me?
Did you find a solution of your problem? If you found it, may you please report it here? I am interested to know it.
Did you look at [link to another question]? Didn't that question help you?
I have the following problem: [description of a different problem]. Can you guys help me?