If you already understand AD, maybe there's not much point for you. The point may be for others that have some background in linear algebra and maybe rings/modu

If you already understand AD, maybe there's not much point for you. The point may be for others that have some background in linear algebra and maybe rings/modules (so they've seen a few non-contrived examples of categories and functors), and who haven't encountered AD. For them, Conal's description is concise and memorable. Again, it's like describing Fourier transforms as an orthogonal decomposition: for someone who hasn't studied linear algebra, functions being "infinite dimensional vectors" will sound scary, and eyes will glaze over. They might prefer to stick to just working at the level of manipulating integrals and using "clever tricks". For those with more linear algebra background, a bunch of the basic theorems around Fourier transforms become immediate, and you don't need to think about them. The "tricks" turn out to be geometrically motivated. So the thing it added is a compact and simple (and therefore pedagogically useful) description of AD for people with the target background.