I've always loved this debate! I've always been pro-screen time but as Twenge states in the article, "it should be a tool you use. Not a tool that uses you."
There are a few arguments I want to make here - having worked with children with developmental disabilities, I've seen first hand the benefits of using iPADs. Whether it be for learning receptive-identifying skills, developing fine/gross-motor skills, using video modeling to teach tasks, or tacting responses, digital applications make learning attractive and engaging for all children, especially ones with DDs. Secondly, my personal view has always been to "go with the times or get left behind." (Un)fortunately we live in a digital generation where the online world has taken over. From doing our banking to sharing pictures of food, the online presence has a huge influence on not only our economy but our social value. Is this a problem? Perhaps. To me, not really.
This leads me to replying your question Beth. I would like to see a comparison study on children growing up in the absence of screen time versus control. I would assume there would be a huge trade-off for those without access to screen time. Our mere social interactions depend on what we see on our smartphones, and it's not necessarily a bad thing!