It's so much easier to build a mental model of a code base with LLMs. You just ask specific questions of a subsystem and they show files, code snippets, point out the idea, etc.

I just recently took the time to understood how the GIL works exactly in CPython, because I just asked a couple of questions about it, Claude showed me the relevant API and examples where can I find it. I looked it up in the CPython codebase and all of a sudden it clicked.

The huge difference was that it cost me MINUTES. I didn't even bother to dig in before, because I can't perfectly read C, the CPython codebase is huge and it would have taken me a really long time to understand everything.