Hey, if you understand Python it makes sense. If you’ve used the PIL before it makes even more sense. If you don’t understand Python, you should probably start by understanding Python.
Of course it makes sense, the code does pretty much nothing. The point is that the tutorial does not teach you about how to remove a background. It's like a "how to cook X" article that just tells you to "order X online" and that's it.
If you want to build a background removal tool from scratch that’s a project of its own. This shows you how to very simply remove a background with a pre-existing tool that other people have spent the many hours to get functional so you can do the five-minute tutorial.
It’s not the Arch Linux way, it’s more like the Ubuntu way.
How to do something - that's what this is. Simple, straightforward, accomplishes its goal.
How to understand something - explaining how and why this works and how you could generalize what this is doing to related projects.
However, even if you are interested in the second choice, this is still useful! Your next step is just to look into the libraries that the rembg package uses.