I have been teaching some EAP classes recently (presessional) and have been encouraging students to use mobile phones at times in class (eg searching for articles using search engines like Google Scholar). I think this is often appropriate and most students use the phones appropriately.
Today, I saw a large lecture where the lecturer made use of Answer Garden (https://answergarden.ch/) to make a lecture more interactive than it would have been. Students could type short responses to questions that are then displayed on a screen as a kind of word cloud. I think this has potential to make lectures more interactive than they would otherwise be.