Face it, the "beta" doesn't matter. At all. The only reason Bethesda put up the sham of one is so when Dawnguard comes out buggy as per Bethesda usual, they can blame the "beta testers" instead of themselves.
I'm sorry but that's rubbish. Bethesda do many things wrong in the eyes of their fans, but they don't often blame people.
I would be
very surprised if, after the dlc is released and fans start to run into the inevitable bugs, they turn around and blame anyone.
I won't be surprised if they keep silent, but they won't blame people.