All good points. I was mainly thinking of Wayland or Xorg crashing during an update, then the update is not interrupted and no one runs into a partial update issue. Your argument is certainly valid outside of that. I told him not to log out of session1 before switching to session 2 as I personally have issues with getting NetworkManager.service to start from TTY on my system. Apparently systemctl start NetworkManager.service doesn’t do the trick for me unless I also have myself logged in on session 1. Logging out of my DE on session 1 and then logging in on session 2 is the ideal method.
(Come to think of it I probably should have opened a thread on that issue.)
I fully agree, though apparently it was enough concern for the GNOME devs to implement this Windows-style offline update. I made a thread last year where I sorta questioned it and got the “safety” argument. I would have told OP just to use terminal but I was worried about getting the “you’re giving dangerous instructions” talk again. And here, too
Of course now I know you need to restart regardless of method used. I was quite inexperienced back then.