The commit contents can tell you what changed, but it can never tell you why it was changed, what the authors thoughts were, what corner cases they took into ac

The commit contents can tell you what changed, but it can never tell you why it was changed, what the authors thoughts were, what corner cases they took into account, whether it was a temporary workaround for something that's no longer a problem... (unless of course the author is a stickler for inline comments, which I also approve of)