It doesn't really act that way, as (1) it can't be accessed with keyboard shortcuts and (2) it's difficult to scan for the desired feature as it's a visual jumble of buttons and text. Oh, and it might not be visible! Sometimes features can only be found in pop-out dialogs.

Having used Office products for 30+, my most-used feature of the Ribbon is Search, because I don't have time to waste hunting through a poorly-organised heap.

But then, you have to learn the sortcuts (if there are any) or click first to open it, then click button/funciton, which is 50% slower.

Also, classic button bars were customizable. You could add/remove/group buttons in any order you like. And there were lots and lots of buttons that were not present in any of the default toolbars. The ribbon is fixed AFAIK.