Yeah, I'm almost positive that this exhibition is intended mostly to raise awareness and create this hype. Go and Chess, for most people, are simple games compared to Dota2, so if Elon is worried about AI and want people to be more aware of the threat he perceives it certainly helps to make this big show and get all those impressions with a game that is considered by the majority of people (especially younger) to be more complex/harder than what has been done before.