I think that argument is often made because it is easy to make. Just because one reads from a paper textbook means one is avoiding distractions? What about phones and their incessant alerts?

One way you can avoid distractions is to limit the features of the device. Pull internet access. The problem here is with the student more than the device. I tend to get distracted a lot when reading a digital textbook too. It takes effort, but also does not looking at your phone when you are reading a textbook.