*Ceres the goddess is an important part of the culture of the ancient Romans, a culture which had an incalculable effect on first Western and then worldwide civilization. Look at Ceres (mythology)#Legacy.  There are statues of Ceres on government buildings in a country that never worshipped her, put up by people who surely never considered her to actually exist because of of her cultural significance and what she represents.  She appears in the works of Shakespeare, who I think we can safely say did not put her there because he was secretly a worshipper of the Roman pantheon. Ceres the asteroid is a rock.  A big rock, sure, but a rock. In space.  Frankly, it's stunning that we even need to have a discussion as to which has superior long-term educational significance.  The answer should be obvious.  
 :As to the pageview ratio, if we allowed a 4:1 ratio to overwhelm long-term significance, Pink would be about the singer.  There's also the many move requests for Madonna (entertainer) as primary topic based on pageviews of around 4:1 in favor of the singer which never go anywhere (if you've never been, pack a lunch, you'll be a while: 2008, 2010, 2012, 2013, 2014). As to "existing" vs "not existing", I suppose that means that James Bond (Canadian football) has more significance than the fictional spy as well.  As does space rock 9007 James Bond, named after the fictional spy.  You know, because they're real.