Fastest is usually the wrong metric. But you'd need experience to know that, I suppose...
But the point is that LLMs giving you 10x the potential code output doesn't have to mean 10x the code committed. It can also be "let's look at all three possible implementations in more detail and decide which is really the best fit for our situation, and commit that one."
That's still 2-3x the velocity, but you get a better result because you went deeper on the paths-not-taken when designing.
I think it's just the wrong metric to optimize for _first_. It's not generally a bad metric to keep tabs on though. Make it work, make it right, make it fast? Or something like that.