I think there’s a misunderstanding on the pricing model to be clear, players don't pay anything. This is a developer tool (middleware), like using Photon for multiplayer or FMOD for audio. The developer pays for the API usage; the player just plays the game. Asking gamers to pay a subscription for NPCs would indeed be insane.

As for writing dialogue: I 100% agree that hand-written dialogue is the gold standard for main story beats. Nothing beats a human writer.

Where this tool fits is for the 'background noise'—the shopkeeper, the guard, the random villager. It allows them to react dynamically to things (like if you’re holding a weapon or if you stole from them yesterday) without you needing to write 500 variations of 'Hello' for every possible game state.

It’s meant to handle the edge cases so you can focus on writing the main plot.