I never said speed was all that mattered. But from my experience, and my other friends in the industry, it is possible to achieve speed while maintaining quality. security, and maintainability. Because these are all things that the AI can look for too. Just look at how many vulnerabilities AI is finding nowadays. Just like any other product manager, you can bring up concerns, ask the AI to look into them, and validate the AI's claims. Just like you would manage a team of engineers. Which is of course still faster than writing everything yourself.
If all you ask the AI to do is produce lines of code, that's all it will do. But AI workflows can be far more complex than that.