Tmux is more programmable. You can write scripts to automate stuff, for example setting up a layout, etc. with a degree of freedom that is not possible with Konsole.
You are probably fine with your setup, not trying to convince you ;-)
Personally: I just like fancy TUIs. One of the first things I programmed was mIRC scripts, might be because of that.
It is common for me and I have aliases set up for 'ls=ls -lah', g=grep -i' and 'x=xsel -b', so the actual commandline looks like 'ls | g "whatever" | x'. Then I can paste or redirect the result into something else.
There are probably better command line clipboard managers, but I just happened to settle on xsel, and it seems to work pretty well. That, and using alt and number keys to switch between tabs gets me pretty far with my terminal emulator.
Have you tried Konsole? I've read it's actually one of the fastest, probably not more than xterm though and you'd need to be willing to use KDE software.
checkout kitty. its FAST. I used to use iterm and once I tried kitty for a day, iterm felt infuriatingly slow.
Edit: Also kitty upstream does not offer a manpage.
I tried a few times to see if I could get any advantage using tmux but always revert back to none at all. To me the scrollback that works 'as expected' without having to remember key combos, and also work with the mouse are a key feature!
edit: That is just my personal killer feature, obviously having a terminal setup that is consistent cross platform and great for stream processing is a given.
The one big advantage of a multiplexer that I can think of is you can disconnect and reconnect from a session. Not something I really need but might be useful.
Ah, clever :-)
In the theme of duplicated terminals, once, I used screen so we could share a terminal session remotely on the same server with a colleague to work together.
My terminal emulator (Konsole) has tabs. It also has tiling features I've never taken the habit to use. It has infinite history and allows me to easily select and copy paste many lines. It has a perfect scrolling behavior: it automatically scrolls, but stops auto scrolling if I scrolled a bit up. I'm used to its keyboard shortcuts to switch tabs. My window manager (KWin) also has tiling-like features when I need to see several terminal sessions at the same time.
I use screen when I need to be able to leave and rejoin later. I almost never need to restore several remote terminal sessions at once, and when I do, I'm happy to just ssh several times.
I feel like my use case is completely covered by the terminal emulator and the WM which are incredibly convenient and efficient. I would expect any layer between this efficient / optimized character display and the programs I run can only add latency. I also quickly feel overwhelmed by a screen full of characters. I think I would miss out on convenience by switching to tmux and it's unclear to me what I would gain.
Happy to be convinced otherwise, though :-)