It's just faster and less distracting. What is a total game-changer for me, is small refactoring. Let's say, you have a method that takes a boolean argument. At some point you realize you need a third value. You could replace it with an enum, but updating a handful of call sites is boring and terribly distracting.

With LLMs I can literally type "unsavedOnly => enum Scope{Unsaved, Saved, RecentlySaved (ignore for now)}" and that's it. It will replace the "bool unsavedOnly" argument with "scope Scope", update the check inside the method, and update the callers. If had to do it by hand each time, I would have lazied out and added another bool argument, or some other kind of a sloppy fix, snowballing the technical debt. But if LLMs can do all the legwork, you don't need sloppy fixes anymore. Keeping the code nice and clean doesn't mean a huge distraction and doesn't kick you out of the zone.