When you check "Automatically hide and show the Dock", your dock will now auto-hide by default. If you move your mouse to your dock's location, however, it will appear.
Auto-hide Menu Bar on Mac
You can check the "Automatically hide and show Menu Bar" selection to auto-hide the menu bar in macOS Big Sur or later.
Something else that's cool you can do is add spacers to your dock!
I always keep an eye on my MacBook's battery percentage—especially since, as a developer, I run a lot of resource-intensive applications.