3. KATHERINE ADDED HUMOR TO THE SHOW
Katherine added humor to her character was way more fun to watch then Elena. Elena never lacked humor and used to get offended while Katherine enjoyed everything and her sarcasm was always on point.
4. KATHERINE WAS A VERY STRONG VAMPIRE UNLIKE ELENA

Katherine was a very strong vampire and she even dosed herself every day with vervain so that she becomes resistant to it. She used her vampirism to stay alive and be stronger while Elena was a very bad and weak vampire and still needed the Slavtores to look after her so that she doesn’t do anything wrong with herself.
TVD Quiz: How Well Do You Remember Season 4?
5. KATHERINE WON’T LET YOU FORGET WHO YOU TRULY ARE

When Katherine landed up in the dorm room of Elena, she saw Caroline packing her stuff as she was scared that Dr.Maxfield will expose her and Elena and will do something worse to them. But Katherin reminds her who she truly is and makes Caroline stay and fight against that creepy doctor. Katherine was a human then and knew what risk she’s taking by staying but she still did. Elena was not like that at all.