The beta is only a tiny part of the full game. The beta continues beyond the battle, as will the game.
They are supposedly announcing the release date in the next video, which I expect to be the end of year holiday period, which is when games sell the most.
If the game was just the beta, I really don't think it would be worth buying. What you're doing by buying the beta is buying the game, and also early access to a year old beta that is full of bugs and will not be updated.