Anecdotally I've found it very useful to use [[ai]] for large refactors, at least around design systems.
It takes out a lot of the work of repetitive changes, and usually gets it correct (or close to). This can be useful for things like renaming tokens, changing structure, duplicating tokens, etc.
It's also useful for auditing the current system. e.g. where are you using certain props, where do you have outliers, etc.