But honestly, the amount of mental energy the author seems to put into this is way beyond anything I would consider needed to use a tiling window manager. Just the base configuration with an application launcher installed is pretty much enough for most people.
And I have never in my whole live visualized the tree in my head. For me at least i3 is a simple and performance conscious way to use my small/old laptop screen, easily switch between the 10 virtual desktops and either use a stack or a side-by-side view. Sometimes I build a very, very simple tree if I use a ton of terminals at once.
I feel like these kind of 'I installed a new kind of desktop environment'-blog posts are just desperate for any kind of content that exceeds 'I installed it and fiddled around in the configuration file to adjust it to my keyboard and then it worked well enough. Over the next couple of weeks I kept adjusting small things to better fit my workflow. After a while I got used to the shortcuts. Oh, and I changed the background.'