Proposition: If you're subscribed to a project or a distribution package, the only bug status changes in another project/distribution that are interesting to you are (1) it's marked Fixed in that other project while not being Fixed in yours (because you could reuse the fix), and (2) it becomes linked to an external bug tracker (because the discussion in the external bug tracker might contain clues for how to fix the bug).
Proposition: If you're subscribed to a project or a distribution package, the only bug status changes in another project/ distribution that are interesting to you are (1) it's marked Fixed in that other project while not being Fixed in yours (because you could reuse the fix), and (2) it becomes linked to an external bug tracker (because the discussion in the external bug tracker might contain clues for how to fix the bug).