I'm using TypeScript. In my case, these refactors are usually small and only spanning up to 5 files depending on how interdependent things are. The benefit with an Agent is it's ability to find and detect related side effects caused by the refactor (broken type-safety, broken translation strings, etc.) and renaming for related things, like an actual UI string if it's tied to the naming of what I'm working on, and my changes happened to include a rename.

It's not always right, but I find it helpful when it finds related changes that I should be making anyway, but may have overlooked.

Another example: selecting a block that I need to wrap (or unwrap) with tedious syntax, say I need to memoize a value with a React `useMemo` hook. I can select the value, open Quick Chat, type "memoize this", and within milliseconds it's correctly wrapped and saved me lots of fiddling on the keyboard. Scale this to hundreds of changes like these over a week, it adds up to valuable time-savings.

Even more powerful: selecting 5, 10, 20 separate values and typing: "memoize all of these" and watching it blast through each one in record time with pinpoint accuracy.

IntelliJ has keyboard shortcuts for all of these. I think how impressed you are by AI depends a lot on the quality of the tooling you were previously working with.