Our Business Case; I am sure there are others:

• we have a product development Jira project. It contains various products and different customers who will get the features.
• we want a particular customer to be able to see the status and progress of his issues. Therefore, we synch these issues one way to another Jira project - it is considered read/only.

Whenever we synch comments, their @mentions are notified upon save of the comment copy. Since the @mentioned people have been notified upon creation of the original comment, the additional notification serves just one purpose - it confuses the notified people.

Therefore, I ask for a per-project configurable @mention notification - much like all other notifications in a project.