"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.