Depends on the code. For things I've already written in specific domains on specific stacks, writing by hand is moderately quicker. I'd never been a faster coder--more of a well-designed and architecturally sound coder.

But the scope of the stuff I'm building now is beyond what I've done before, so yes, it is better and faster for the agent to do it. Software with agents is an industrial process now, rather than an artisanal one, so it's a better fit for some kinds of things than others.