GhostSalsa
Emperor
Personally, I would start Piety only after getting the Settler policy from Liberty and starting to expand. At that point it's probably worth it at least for some civs, especially the Byzantines*. If you get a good amount of culture going, you will be able to eventually finish Liberty/Tradition and Piety before switching to a later tree, like Rationalism.
Yes, this is my conclusion as well. Which means, with going down piety as a second/blended tree, you will be mostly disregarding or ignoring Aesthetics/Exploration/Commerce because you're already in Renaissance, near Industrial by the time you finally close Piety. Which makes you wonder why you would even want a religion, if you can't synergize it with a culture or diplomatic victory. As with G&K, religion becomes only appealing if you can snag it for free and ignore temples.
I wanted to see how the game would play out without racing to become a pre-0BC superpower but next game I will be going straight for ToA or Hanging Gardens, as completely usual. I'll be making sure my win is locked by turn 100. Boring!