I'm not convinced; let's suppose it's not a problem to always play Baker first, since that's a cantrip and you expect to see it about as often as Butcher, although Rebuild cycles enough to make that not guaranteed. Even so, Butcher turning Duchy into Province isn't better than doing it with Rebuild - Butcher is terminal, and you need to draw it with your Duchy, whereas Rebuild is non-terminal and only needs to be drawn with not all of your Duchies. Add to that the fact that instead of Baker and Butcher, you could have had two more Rebuilds (or Duchies, if that pile is nearing its end), and the whole thing just sounds worse than straight Rebuild.