yes judging her by modern standards or any standards its hard to call her a companion, she is like Astrid, but she was the only person associated with the 8th Doctor, would could in any way be called a companion, so the fans call her that anyways.Can you call someone a "companion" if they don't travel with the Doctor?And after Donna caved in season 4, Grace now holds the honor of being the one companion who said 'hell no' when asked to come travelling.