Sure, they might help you onboard into a complex codebase, but that's about it.
They help in breadth, not depth, really. And to be clear, to me that's extremely helpful, cause working on "depth" is fun and invigorating, while working on "breadth" is more often than not a slog, which I'm happy to have Claude Code write up a draft for in 15 minutes, review, do a bunch of tweaks, and be done with.