Thats a black or white fallacy: I think carried to the extreme it would be like me making the claim that kids who use tablets will become software engineers. My argument, is that screen time makes kids better at interacting with screens.

For clarity to your point; I think it would be hard to argue that among kids tested playing piano that those who had an interest and practiced more would sound better statistically. Your toddler may not be davinvi, but they should end up with better fine motor control and maybe learn to enjoy expressing themselves in that medium.