I know that when someone claims that a question is a duplicate there is an option to edit the question to make it more clear how it's different from the other question. Sometimes it can be clear how to edit a question to show that it isn't a duplicate, but other times, even if I might feel that my question isn't a duplicate, it might not be clear how to edit it to make it more clear to others that it isn't a duplicate.
I think if the similarities between two questions are pointed out, then it could make it easier to tell what edits should be made to a question, in order to make it more distinct from what it's claimed to be a possible duplicate of. This is the reason that I think we should try to mention what a question has in common with another question when linking a possible duplicate.
What about those answers.
- helpful?, see also the FAQ. Sometimes it's certainly a roundabout, but many don't wish to, and are not obligated to, debate their reviews in the comments - if they are wrong another reviewer will fix things.