Why should anyone bother? The AI cannot win a religious victory. It's not even designed to try. It just spams apostles to convert cities and attacks other apostles when it encounters during these attempts. It has no offensive or defensive strategy, insomuch as there's not much of one.
The thing is, everyone will just vote with their gut. We have right here articulated problems with the religious victory condition, and sure enough we still get responses s that dismisses those well-articulated issues out-of-hand, like Scaramanga.
You don't need a religious victory to have a religion focus, any more than you need an economic victory to justify a civ's gold focus, or a production victory to justify a production focus (and to anyone who feels the urge to point out that a science victory is a production victory, you're rather making my point). Same goes for Theocracy.
It's fine to argue about a premise, but the execution falls way short of being meaningful as a victory condition.
There's that, but there's way more than that to send back to the drawing board. We can talk about all kinds of things that add depth to military combat that is positive before we start getting to the AI not building planes or marching forward with lone catapults. There's surrounding to siege it, pillaging, modifiers like terrain and flanking, encampments, using spies to create unrest, etc. You have some management to do with strategic resources and creating choke points and manufacturing a casus beli. You know about all waging war (lots more than I do). There's at least the veneer of a a series on integrated systems.
With RV, there's just not much to excel at that would distinguish a good strategy from a bad one. There's not much reason why religious victory between civ's with equal faith infrastructure shouldn't be a stalemate. We don't need to bother with Scaramanga's delicate balancing act. I can't fault the AI for spamming units if that's all they can really do. If someone's hassling my civ, I just park inquisitors and damaged apostles in the city until they leave or I am ready to make another surge. I can flip my cities back tout de suite.
If your main beef with RV is that the AI is bad at executing a strategy for it then I think that applies to all victory conditions.
It has been my experience that victory conditions exist solely for the player, and the AI is just there to serve either as obstacles or supporting cast for the gameplay experience the player has on their way to victory.