Back in the day...(when I student taught, my hands were stained at the end of every day with overhead marker.) it was like playing whack-a-mole going from group to group, trying to keep them on task, trying to troubleshoot all the groups at once, not feeling effective, correcting the same mistakes over and over and over. Students were frustrated, because if I was helping another group, my back was to them (horror!!) and some students simply have difficulty delaying gratification. It didn't help that I was so easily distracted, that I lost my train of thought every few seconds.
No, it's not a silver bullet. (THERE'S NO SUCH THING!!) But it does allow for a much smoother and more effective process. My explanations are in writing, so if they forget what I said three or four seconds after I've moved to the next group (please, tell me you understand) they can refer to the comments. Classroom management can be deferred -- they know in advance that Google tracks EVERYTHING, and issues will be handled, and I always follow through. The edge is that none of those issues need to be handled immediately, in front of classmates. No power struggles, no risk of losing face (you or the student...interpret as appropriate...) Most of all, no room for denial, so no emotion needs to be involved on your part.
Pedagogically, we have collaboration and critical thinking, and without having to decipher their classmates' handwriting, they are able to focus fully on developing their writing skills. As I move from screen to screen (group to group) if I notice common struggles, it is much quicker and easier for me to address the class as a whole.
As technology tools go, This one is a keeper!
Let me know how it works for you!!