What's the usecase for this one? You know that most desktop computers come with a physical dialpad that contains numbers and letters …
It’s not just for entering numbers, it’s for dialling a phone number and then ringing it, using OS X and iOS 8’s new features.
Still, why wouldn't you just dial the number by hitting the number keys on your keyboard?
You can. You hit the numbers on your keyboard or you click on them with your mouse cursor. But, this is for dialing from your mac but with your iphone. That's the speciality of this keypad. Not the numbers on it.
You can also add a Today Widget → Easier inserting numbers.