Control center is responsible for drawing a bunch of the ui on the top right of the menu bar, things like the clock (many comments here seem to be saying this is related to showing seconds), Wi-Fi, sound settings, etc.
It also shows the annoying overlay bit when you accidentally open it :D
I think part of the confusion is that there's the feature "Control Center" and the process controlcenter so you would reasonably think it's only involved in the marketing feature's UI.
It also shows the annoying overlay bit when you accidentally open it :D