The Control Center is absolutely worthless to me. I don't know about others but all its default controls are either already available on my menu bar or on my keyboard and the couple I would have liked to add (like Weather) are unavailable in the Dock and Menubar preferences to add.
As for third party and seldom used app menubar items I keep them concealed using Bartender 4.
I would move the Control Center menubar icon to "hidden" in Bartender 4 but "macOS prevents the Clock, Control Center, and Siri from being repositioned by the user."
I haven't paid much attention to it, but looking at it now (on the new M1 MacBook Air). There certainly are some duplicates, but one could choose to remove them from the menubar and leave them in Control Center if desired. That would keep the menubar from being overly cluttered for less-used items or for those who have a lot of extras there. I would prefer to remove something from the Control Center though if it's something I want on the menubar. Wi-Fi, for example, is something I like to have there always. Bluetooth, i don't care about so it's fine in the CC and I have the option turned off for it to show on the menubar. Same thing for sound volume.
This is new here... this new MBA has a keyboard toggle for Do Not Disturb (F6) and one for Dictation (F5). Spotlight now is toggled by F4. Missing are the keyboard brightness controls, so that is definitely needed in CC. I don't mind having the sliders there, even though I do still have keyboard controls for Display Brightness, just so I can see the level they are set to, even though realistically I'm setting to what my eyeballs like anyway. Since it is possible to force the F-keys to work by default as function keys rather than hardware controls, those items in CC still can serve a useful purpose. In any event, it appears that Control Center is intended to function in part to replace controls that Apple has removed from the keyboards for the Apple Silicon line. I would assume future keyboards for the desktops will be similarly re-configured in the way the MBA has been.