This is one of the most promising uses of LLMs that I have found in my own work. Many times I have an idea for a refactor or even a feature but I have this mental reluctance just due to the amount of code I would have to write. Like, I have this counter in my head on the number of key-strokes it will take to write a wrapper object in several places, and I hesitate.

Just being able to tell an LLM "rewrite all of this code using this new pattern" and then dozens of code sites are correctly updated is a huge help. It makes me consider bigger refactoring or minor features that I might normally skip because I am lazy.