It's Britney Bit!h. People who go to the show don't care if she is singing live or not. They go to see Britney. As for the dancing, its nice to see so much energy. I've seen some of the other performances and they looked good, especially baby one more time/opps!
I wonder if they will release a DVD of one of these shows. I really hope so.
I am sure they will once the residency is over. They did with Celine and Cher.