By "he can do it from the bug page" do you mean "he will be able to do it from the bug page in the future"? I don't see how to do it now.
Perhaps translations is another use case. A project's maintainers don't use Launchpad at all, but the Fooish and Barinese translators of that project both decide they want to use Launchpad for their translations. The Barinese translators get to Launchpad first, and ... what do they do?
By "he can do it from the bug page" do you mean "he will be able to do it from the bug page in the future"? I don't see how to do it now.
Perhaps translations is another use case. A project's maintainers don't use Launchpad at all, but the Fooish and Barinese translators of that project both decide they want to use Launchpad for their translations. The Barinese translators get to Launchpad first, and ... what do they do?