"Beta" is a very loosely-defined term. Gmail was in "beta" for years. All it really means is that it isn't the "final product".
My fear is this is because of the 3 million beta users and grand views of the masses.
I guess my main point is that 3 million users might not be the best for a beta game. It might work in the end, but I think Minecraft might get bogged down with 3 million users making suggestions to a non-complete game.