I think most often people have some vibe coded stuff that kind of does what they want but they don't really understand what it all is and how it works, or any confidence it can be made into something useful, so rather than spending time cleaning up AI code they just use it to grasp the idea and write it themselves. Whether any time is saved by going through this process with the AI seems doubtful to me. Sitting down with pen and paper and thinking through things would probably be more useful.