Tmux is good because:
1) sessions stay running if you disconnect
2) window management - you can split your screen, have an octobox a-la redzone style, and focus/unfocus etc.
This is based on developing on a remote server - but even locally, I find it invaluable. Multiple terminal windows are fine, but some times you want multiple windows. Even in a pre-ai world, you might want to run a process, see the code, edit, and maybe have htop or something like that. If you ever NEED multiple terminal windows for the same thing, tmux is really the answer.
One reason I find it hard to grasp is that when I work on Windows, it's almost always through RDP or VNC. There is never any question of a terminal (or a process launched from it) staying open between login sessions, because it never depended on any particular connection to begin with. It's just there, on the desktop, which might stay up for months before I need to connect to it again. Any terminals or other processes I launch on that system will be there until I close them intentionally, or until Microsoft decides to reboot the system without my permission.
So when I dip my toes into the Linux world, the first thing I do (or rather ask an LLM harness to do, being much less familiar with Linux than I am with Windows) is set up an RDP host. That way I can follow the same basic workflow on both OSes. I don't need to do anything special with terminal windows.
I guess if I were running truly headless systems that don't even have a VGA frame buffer, I'd be more interested in multiplexing. But so far I haven't had to do that, and would probably resist it because a persistent desktop strikes me as better in general than letting applications including terminals worry about their own lifetimes.
I have been in RDP land but I would never go back unless required (windows). While it could just be personal experience/failures, latency was not good and reliability was not good. Things are probably better as of late though I hesitate to assume software has improved... It is just much simpler to live in the terminal for dev work, especially with agents. That being said, I use MacOS and Windows daily for non-dev work. Either way, your points are valid, and whatever works for you works for you friend :)
This is based on developing on a remote server - but even locally, I find it invaluable. Multiple terminal windows are fine, but some times you want multiple windows. Even in a pre-ai world, you might want to run a process, see the code, edit, and maybe have htop or something like that. If you ever NEED multiple terminal windows for the same thing, tmux is really the answer.