The reason these exist is because these topics are big and somewhat inaccessible, but they are relevant to people who wouldn't learn them in the normal course of their lives. You wouldn't expect to see as many for something that is commonly known in a given field and doesn't matter to people outside it, or things which are already quite accessible without trying to make them super-friendly.

Here's an example that does something similar with the law: http://lawcomic.net/

You'll notice that the law has the same characteristics I identified earlier in technology — it's very relevant to ordinary people, but it's large and inaccessible enough that most people don't really understand it and setting a law book in front of them wouldn't help.