Most users on the other hand, especially (semi)professional users, work a lot faster by using keyboard shortcuts. To be honest, I know no one that doesn't use undo/redo shortcuts in favor of an interface button. The main reason is that it just works a lot faster to also use your keyboard. And in a world where time is money, working more efficient is key.
But, I could think of one valid reason to be able to use a button rather than a keyboard shortcut; a physical disability. If a person has no, or limited, functionality to his or her left/right hand, it could be a blessing to have a button in the interface. I do know one person that fits into that category, but she uses a pen with the undo/redo function under the buttons on the pen. Her mouse has multiple macro's attached to it as well, including undo/redo.
I think it would probably be a really good thing if you would start learning to use your keyboard as a part of your workflow. Once you've mastered it, you'll notice how much faster you can work. Win/win situation for you I'd say.