I agree that they have replaced a great many things. I still carry a camera, though, as the camera can do a good many things that my phone can't. That said, as with some inventions, the problem isn't the invention, the problem is to the use the invention is put to.

In this case, I wrote in response to Jared E Brock who has written a number of pieces about how smartphones make us all unhappy and how he dumped his years ago and has never needed it since. He lives on an Island in Asia somewhere. I think he is unaware that we need cell phones to survive now.