What about reversing your question, that pianists have better finger control and thus can learn typing fast more easy?Sounds logic to me.
There really is no connection in my opinion. Typing is much easier than playing piano as your hands can stay still the entire time while you type in single position. Being good at typing doesn't mean you have the aplitude for piano just like riding a tricycle doesn't mean you could ride a motor bike. You probably could say, if you have no ability to to type on the keyboard then probably you cannot learn to play the piano.