The crew isn't just there to fix stuff that breaks. They're performing routine preventative maintenance constantly as the vessel is underway. That's in addition

The crew isn't just there to fix stuff that breaks. They're performing routine preventative maintenance constantly as the vessel is underway. That's in addition to performing inspections that would be difficult to do remotely, and training to handle emergencies that need to be dealt with _right now_ (you're not going to flying a response team out to a ship that has caught fire in the middle of the ocean... at least not if you expect to recover anything... that sort of thing needs to be dealt with by people on board).