Can social revolt ever be useful?

I'm talking about taking Piety then switching to Rationalism when it's available; or a similer situation with the later opposed policy branches.

The only time I can see this been useful if if you really want to found a religion and the race is on. Obviously you won't be doing it for culture since you're wasting a bunch of it in the process. I suppose if you're playing as Egypt or otherwise have a happiness perk for your religion you might want to build religious happy buildings quickly and possible sacrifice culture for gold if you go for the "temple grant gold" policy - if you really want to go that far. It doesn't seem like a very good idea however.

I don't know enough about the late game branches because I hardly ever play that far before calling it a win.

Anone have any ideas? Have you ever used revolts to any success?

One turn of anarchy should not, in my view, dissuade you from switching between conflicting policy trees, but you need to have a good reason for doing so, since you will have sunk a big chunk of culture into a policy tree you are abandoning. (Let's ignore abuse of the Rationalism finisher, which the Fall patch is going to fix.)

Using your example, if all you do is take the first two policies in Piety (quicker temple and shrine production with the opener and Organized Religion for extra faith) for the purpose of founding or enhancing your religion, you should have gotten whatever Piety benefit you were aiming for by the time you hit the Renaissance. So, you wouldn't be losing anything meaningful by switching to Rationalism and enduring one turn of anarchy. I haven't done this, but it would be a rational course.

If you anticipate going deeper into Piety (e.g., taking Theocracy for the temple gold or Reformation for the culture boost), I would rethink things, either before switching out of Piety or, even better, before opening Piety in the first place. If you need the extra faith, consider skipping Piety and opening Patronage; befriend religious CSs with cash and quests initially and later pledge to protect and Aesthetics.

Yes, Rationalism is optimized for science, but you don't have to take it to get good science rolling. So, one course is to take Piety with the intention of skipping Rationalism altogether; when you hit the Renaissance, beeline a few more techs to Industrial, open Order, and take Planned Economy (factory science boost) as your first policy. Or stay in Patronage and take Scholasticism for science from CS allies. Mercantilism for extra science from money buildings can also help. None of these will fully match Rationalism, but they can help fill gaps (particularly the factory science, which I really like, since I often want to build factories as soon as I can anyway).