Earlier quoted context omitted.
If you have a job where you arent allowed to commit directly to master / development branches this is probably how they enforce it. It keeps juniors from pushing bad code without peer review. It forces developers into doing PRs instead. Protected branches are the first thing we setup when we make a new repository at work once we hit the "getting good enough for production and autobuilds" stage of development.
Yeah but the concept of this post revolves around individual developer github account (not an organizational one). What circumstances would you be protecting your own private repo?
You can still use the same ruleset to force yourself to write code independently with a sane process though. I put repository rules on my personal private repositories on BitBucket and GitLab. Once you're used to a specific process and it works nicely for you, it makes sense to repeat. This way you don't ever pollute your main branches with in-progress code by mistake.