In short, it's significant progress in the OpenAI team's quest to build really effective self trained artificial intelligence. Conquest in a problem space like this has real world applications that could translate to things like extremely effective artificial limb dexterity (according to the talking points from the event).
Dota 2 was chosen because it's a nice combination of pre-determined rules (to an extent) and an extremely complex problem set of possible moves and actions. Dota's development team also was really supportive to this effort and they have an API that suits the Open AI team's purposes of interacting with the game really well. Great fit all around.
Dota 2, especially when played 5v5, is orders of magnitude more complex than in terms of possible decisions and moves than Go.
Dota 2 was chosen because it's a nice combination of pre-determined rules (to an extent) and an extremely complex problem set of possible moves and actions. Dota's development team also was really supportive to this effort and they have an API that suits the Open AI team's purposes of interacting with the game really well. Great fit all around.
Dota 2, especially when played 5v5, is orders of magnitude more complex than in terms of possible decisions and moves than Go.