Of course. It blocks the founder's benefit from your opponents. You can also study civics that give bonuses.
I am currently Spain and going heavy religion. I get 4 gold from every foreign city of my religion, and a relic for every city I convert that has 10 urban citizens. It also links to the military path, as you get extra points for conquering settlements that are of your religion.
I think religion is fine. It's like anything else: if there is a lot of competition, you need to find another path less crowded.
Converting your cities solely to "blocks the founder's benefit from your opponents" is not a well-designed system.
Consider a game with four players: A, B, C, and D, each with different strategies:
- Player A: Focuses entirely on converting Player B's cities.
- Player B: Focuses entirely on converting Player A's cities.
- Player C: Splits efforts between converting Player D's cities and maintaining their own.
- Player D: Splits efforts between converting Player C's cities and maintaining their own.
In this scenario, the likely winners are A and B, while C and D struggle. Even though C and D might perform well in a one-on-one match, the dynamic changes drastically with more players. Those who ignore their own cities' religious integrity and focus solely on aggressive conversion gain a significant advantage. Meanwhile, C and D waste resources countering each other, ultimately weakening themselves while A and B prosper.
Adding a single policy that provides a marginal benefit for maintaining religious control isn't enough. While the policy offers decent advantages, it requires substantial investment in missionaries, culture/ civics, making it costly and inefficient.
It feels historically inaccurate that, during the Age of Exploration—an era marked by intense religious conflict—players can neglect religion in their core cities without consequence. Religion becomes merely a tool for military purposes (you get military points to convert your cities on distant lands) rather than a reflection of cultural or societal influence. Converting distant lands should be a secondary concern; maintaining religious cohesion at home should carry more strategic weight.
A more balanced system would reward players who invest in their core lands cities while still allowing strategic flexibility for offensive religious play. As it stands, the current mechanics encourage a counterintuitive approach that should definitely be improved, because playing converting your cities not in distant lands will not be optimal in 99% of scenarios.