You're acting like setting it up by hand means you're diving into the code and doing it yourself. In truth it means just picking the caching extension that matches your needs the most, and if you don't know what that means picking the most popular one will be just fine.

Personally I like this. It means that I was able to pick a caching engine that integrates directly into nginx, so that when I write a new post or edit an existing one the extension invalidates it directly in nginx. This means for the vast majority of my site the content is being served directly from nginx's memory cache. My performance is awesome. If they didn't go with an extension approach that would not have been nearly as easy to accomplish.

...because getting caching right on a dynamic database-driven content management system is so easy.