Difference between Flags "A Duplicate" and "Should be Closed... Duplicate of"

Question

For awhile I've been confused by the two flagging options for duplicates. What is the difference between selecting

a duplicate...

versus selecting

should be closed...

then

duplicate of...

on the flagging menu?

Do the two flags indicate anything different to the moderators who review them?

Do they do anything different in the system? For example, I've noticed that only sometimes does my flag create the automatic comment "possible duplicate of...," but I can never remember which flagging process resulted in it.

If they work exactly the same, is there a reason that we have both options?

Is it preferred that I use one or the other, or does it not matter whatsoever?

Answer 1

They're essentially the same. Regardless of which one you choose, the next window title is:

Flagging > Closing > Duplicate

Users who do not have the "close vote" privileges can still click on "flag" to suggest that a question is possibly a duplicate of another.

Only those with the close vote privileges can actually close questions as duplicates. You can see the button change from "Flag Question" to "Vote to Close" only in this case.