"Is anyone still using emacs?"
I use emacs --daemon instead of tmux inside my agent sandbox for session permanence and portability. A full editor rather than a layer between me and my editor. I can even waypipe the client windows if I want mouse support.
I do the dinosaur version of this, with screen and xpra. Works great. CC and codex being terminal-native may make terminal-based (or at least terminal-comfortable) editors seem more natural to a broader set of people.
Why use screen? Just leave your emacs --daemon running, and when you reconnect, run emacsclient and all your buffers are back. And you only have to learn one method for arranging frames rather than both emacs' and screen's.