Think we're pretty close to the point where we'll no longer need to prompt AI to refactor or review the refactoring if it's done within tight constraints i.e. absolutely no change to functionality. But when functionality changes may be acceptable as part of it, it's less clear - in my experience AI isn't at a point yet where it can always be trusted to "understand" what the requirements are (including to what extent they can be allowed to evolve), what is or isn't acceptable in terms of user experience etc. That's where human review is still useful and in many cases, essential.