If someone came to me and said "I ran these and I see XXX was the most prolific committer and they left X months ago, what will be do???" I'd have to work hard not to laugh.
Since these snippets are self-described as ways to get familiar with the code/projects I wanted to provide the counter point. Most of those snippets do not at all paint the real picture and for all the repos I tested it on they paint the opposite of reality.
I know these codebases like the back of my hand, the purported purpose of these snippets is to better understand the codebase, I can tell you they don't work for anything I tested them on. Maybe they work for other codebases but the sample size I have access to says they don't work for me.