Self-hosting is something that is important to me. You should self-host, too. It teaches you a lot. You'll learn about networking, maintaining large numbers of services, programming, and more. How deep you want to go with it is really up to you.
The Pi server rack is something that in my opinion would make a good entry point for those who want to learn more about managing a system for themselves. It offers a taste of reality insofar as needing to administer and maintain documentation for multiple machines; but, it maintains simplicity for a beginner by not jumping immediately into software containerization, while doing essentially the same thing.
You could use a system like this to teach yourself about cluster computing—about how to run tasks in parallel across many machines. There are lots of reasons to build a setup like this, and it is really quite enjoyable. I recommend you try it yourself!