Gadgets should be configurable via the preferences window. The page curation toolbar isn't. So anyone with NPR rights that doesn't want to use it is constantly annoyed by its presence (even if they never use it and prefer twinkle)
Should be 'on' by default after the New Page Reviewer userright is granted, but should be able to be unticked in 'Preferences' so that it can be disabled entirely by editors who don't want it to pop up ever (New Page Reviewers or Admins who prefer to use other tools).