The second paragraph explains why this exists, and it's not to provide a useful implementation of Git.
> I wanted to compare what it would look like in Go, to see if it was reasonable to write small scripts in Go – quick ’n’ dirty code where performance isn’t a big deal, and stack traces are all you need for error handling.
It's a toy problem that's just big enough to be interesting. Comparing it to Hoyt's earlier Python implementation of the same problem lets him evaluate how Go would fit into a certain place in his development workflow.
> I wanted to compare what it would look like in Go, to see if it was reasonable to write small scripts in Go – quick ’n’ dirty code where performance isn’t a big deal, and stack traces are all you need for error handling.
It's a toy problem that's just big enough to be interesting. Comparing it to Hoyt's earlier Python implementation of the same problem lets him evaluate how Go would fit into a certain place in his development workflow.