[SketchySeaBeast]

> is a huge help in understanding code you haven’t worked with previously

This is huge for me. As someone who takes on already completed projects, it's a huge help with debugging and understand what's going on without requiring you to know the whole system forward and backwards. Sure, you still need to build a mental map of the general code flow, but you can look at a single function and clearly see the obvious inputs and outputs. Combine that with a a stack trace and you can debug that method as a single unit and then start to look at where it's called and what its downstream effects are. You don't need to start from the very beginning of the call and then follow it through, keeping mental track of what is available and in what form when and where.