Q:

Why can't gold tag badge holders "instantly close" for non-duplicate reasons?

After reading this answer to Increase close vote weight for gold tag badge holders, I was able to better understand the reasons that led users who have a gold badge in a tag to gain the ability to close instantly as duplicate. 
But this also led me to believe that these users can identify when a question in the tag where they hold a gold badge is "unclear", when this question is "broad" and perhaps when the question is "a simple typographical error or can no longer be reproduced".
Why not expand this ability to these reasons as well, as long as they are inside the tag where the user holds a gold badge?

A:

Closing as a duplicate is different to other close reasons as it directly helps the OP, they get an immediate answer or answers to their question. The other close reasons don't do that, so for that reason Stack Exchange requires that multiple non-moderators evaluate the question.
There is a proposal to Swing the gold hammer even more. You could vote for that if you feel that gold badge holders should have increased powers.

A:

Gold tag badge means the user is probably very familiar with that tag, and seen lots of questions with that tag over the years (usually that's what it take to get a gold tag badge), so if there is a duplicate, they're most likely to know about it, and to usually be correct.
However, duplicate is a special close reason: it's the only close reason which isn't due to the question being off topic for the site. The question is on topic and might be excellent, just already asked before. So the power to close using such reason is less than the power to decide "this is off topic here", which still requires five high rep users of the site (or one moderator). This is a good balance, since one person, who is not a full moderator, should not make such decisions alone, no matter the experience they have in one tag.

