I almost bounced off this link because none of the tabs have any content in them. I clicked through to the GitHub and it also doesn't tell you where to get started. Finally I came back and found the PDF. Maybe the title could be "Pen and paper exercises in machine learning (PDF)" to help you know what you're looking for?
Direct links to arxiv PDFs are discouraged, since they are immutable. If the author uploads a v2 to correct an error, your link will still point to the old version.
No, that link will always point to the most recent version.
Even if it was a link for a specific version, I'd still post it as arxiv's landing page isn't designed for those who need to jump to the content right away. It's extremely cluttered and hard to navigate. I couldn't care less if the PDF got some arbitrary fixes in an unknown future. That'd be arxiv's problem.