Why do people say that Shiv is so good?

I'm interested in playing Shiv but I'm not really sure what makes him so good. AFAIK his only really good trait is his damage. Everything else that he has is either meh, or is easily stopped. He has bad range, bad mobility, good vitality with life steal but when opponents run anti-heal it kills him, doesn't really support the team. What makes him so good?