If the agent is at least reasonably good at your language, the errors that are getting caught at compile time in a language with reasonably expressive types like Swift should be actually catching and eliminating bugs without having the run anything. It seems like the ceiling of how long an iteration takes would be lower, but the floor would be a lot higher, and then you're making a bet that the number of iterations needed won't be so high that it takes more time overall to get things working, which doesn't strike me as obviously true (and that's not getting into how fast the final product will be when the agent is finished, although both Lua and Swift seem like they're most heavily used in domains where you don't really have an alternative choice, so it's not easy to really compare these anyhow)