That depends on how you look at it. Sacrifice always has a consequence and is a last ditch attempt at achieving a goal. The consequence is guaranteed to happen because it wouldn't be a sacrifice otherwise, but the goal may not be achieved. To me, the Airbenders being captured was another sign that this was the lowest point in the show. Nothing was going right for the heroes and survival was looking less and less likely with each passing event. BUT, because the consequence of her sacrifice, the guaranteed thing to happen to her for trying it was taken back, it removes all pretense of the "sacrifice" ever mattering.

I wouldn't say that's necessarily true, because at the time of her sacrifice, she had no idea that if her bending got taken away that it could be restored. So, she took a huge risk with that and I don't see it as killing her sacrifice, but rewarding her for her courage.