There is not really a mention as to how I, and I believe many other, really use group chats. Yeah. Of course I have a couple group chats with people I know... But these do not compare to the ones that I'm in that have been formed entirely online.
The dynamics might be similar but in my experience online (born) groups tend to be much more chaotic and there's a drift of members coming in an out that's quite interesting. For many that I've met they might chat everyday with the people in the group to simply disappear one day and never come back, or perhaps come back a year or two later (if the group is still alive).
I think it stems from the fact that for the journalist "group chats" are linked to apple's technology "iMessage". But for me, when I think of group chats I think of discord servers, IRC channels, etc. I mean, Ive been using group chats for years before the smartphone came, and the experience I had back then is pretty much identical to the one I have today. I was the kind of kid that was in front of the computer all day anyway.