Why use a nailgun instead of a hammer, if the nailgun still requires supervision and handholding?

Example: Say I discover a problem in the SPA design that can be fixed by tuning some CSS.

Without LLM: Dig around the code until I find the right spot. If it's been some months since I was there this can easily cost five minutes.

With LLM: Explain what is wrong. Perhaps description is vague ("cancel button is too invisible, I need another solution") or specific ("1px more margin here please"). The LLM makes a best effort fix within 30 secs. The diff points to just the right location so you can fine tune it.