"screens" can be great for research and there is a lot you can learn online.

The main problem mentioned in the article you link to seem to be distraction from what they were supposed to be doing.

Distraction is not always bad and kids can learn a lot by being distracted by something that catches their interest. it depends on the approach and its more of a problem following a fixed curriculum in a classroom. Probably more of a problem for uninterested or younger children.

I think video can be a big problem, particularly given the tendency of sites to try to keep you there.