I've seen a few people, both here and at civfanatics, saying that policies that are culture/reduce policy cost focused are wastes of culture for non utopia games. What's the general opinion on policies that do little else but help you get more policies? Personally, I see it as an investment you're making now so that in 3 eras time, you'll have more policies than you'd have otherwise
It depends on when you acquire the policy, how much it costs etc.
There is no set way to play Civ V, but there are certain ways that are more useful for certain victory conditions or civilizations.
For example several of the policies under the Piety and Freedom branches increase your culture per turn, but you obviously lose the opportunity to select another policy. You have to decide whether it's worth selecting those policies based on your civilization. For example, it may be worth activating mandate of heaven (half excess happiness added to culture) if you have high happiness. This may suit civilizations built around small cities with lots of happiness buildings and wonders (Notre Dame, Tal Mahaal, Eiffel Tower etc) whilst reformation (+33% culture for all cities with a world wonder) may suit a spread out civilization with lots of cities with world wonders whilst constitution under freedom (+2 culture per world wonder) may benefit a civilization that has focused significantly on world wonders.
With respect to reducing the future cost of policies, Christo Redeemer and the piety finisher (-10% policy cost) may be very useful if used as early as possible, as they may reduce the cost of 3-4 policies depending on how you're playing your game.
Ultimately, there will be people who tell you that they always do something, but it just suits their style of play rather than is a set rule. For example, many people state that they always build a scout early on. However, I prefer a smaller civilization with a few large cities and find that there may be little benefit to me building a scout rather than just using my warrior. It doesn't mean that either approach is wrong, just that they attack the game in a different way.
If you get through Piety early enough and still focus a bit on culture, it will probably lead you to more policies eventually. It depends on how you play the game. I've not done the math on it and there are too many variables. However, it will take you a while to get the return on the investment and therefore pushes back the benefits you'd otherwise be getting from other policies sooner. I've been meaning to try to create a large empire based on culture and go for a different kind of victory. It's an interesting, albeit unfocused, strategy.
That is my usual Aztec strategy. Keep everything but Tenochtitlan as puppets and you can work wonders with happiness from policies. Garrison everywhere with purchased scouts like a conveyor belt. If the capital gets far from the front line a barracks+armory means 3 move speed scouts, and you should be building roads like a maniac for the liberty trade happiness mid game anyway.
It becomes a race to see if you win by domination or culture first. This is the only strategy I'm good enough with to often win on deity; so far.