Are you sure that would work for every Chrome user? Chrome tests many different variations on different users and they are constantly messing with Chrome and ChromeOS via automatic updates. On a Chromebook I have in developer mode, using the Crouton chroot script, for many months, through several "updates", cookies could no longer be blocked from the address bar, only through Settings and only on a per site basis; it became impossible to globally disable cookies, the setting would automatically revert back to enabled! After the latest update, I can now finally gloablly disable cookies again and disable from the address bar (though this requires more clicks than it once did). Sometimes they release "updates" and the stuff is still broken. By the next update they have fixed it. In the interim we have to settle for unfinished software. In my opinion, Chrome is not one program, it is constantly changing unfinished work and not every user gets the same "features".
I block cookies using a local proxy. I cannot rely on Chrome "features" for anything privacy-related. They just keep changing.