You have an issue and in time there are let's say 5 duplicates.
You see all these issues in the lists and managing them all can be a bit frustrating.
Maybe we need a merge button so we can merge the duplicate(s) with the original and close the duplicate(s) all with one click
If I say merge then you automagically think of a split issue option to. (create 2 or more subtasks for the original issue with some sort of split wizard)