Is hip-hop dancing a Sport or an Art?

During my presentation I was asked a question: "Is hip-hop dancing a sport or art?". In my opinion it is definitely a sport. And now I'll try to explain why i think so. Let's look at definition of SPORT in dictionary: a physical activity that is governed by a set of rules and often engaged in competitively. Sports commonly refer to activities involving physical exertion and skill and where the physical capabilities of the competitor are the sole or primary determiner of the outcome (winning or losing). There are Hip-Hop competitions that have their own rules and regulations which must be followed by teams that take part their. (So this is an activity with a set of rules). Also all hip-hop dancers train a lot and have good physical skills that help them to reach better results. All competitions in this fields have strict marking criterias. Referees have their papers with all the categories where they mark a performance of the team according to those criterias. And of course a team that earned more points wins. So all the points from SPORT's definitions are included in Hip-hop that makes me think that Hip-hop dancing is a SPORT. If it was ART there wouldn't be competitions; the effort would be made for making estetic product and to performe it. No referees, no marks, no rules...That's not about a Hip-hop. Do I sound convincing?