Love this ever since I found it on 'Learn Linux TV' on youtube. I have an ultrawide and I'm using this to help me become more proficient with the CLI. I can remote SSH, manage LXC's, rean man pages, run local commands, and more, all in the same window - or navigate multiple windows!
with tmux you can run persistant sessions on a remote terminal; if you have a big screen it can be very handy to split your terminal into panes. for example read man pages on the left, and try out the information on the commandline in the right pane.
I have a tmux session on a server from my job... since 8 months ago and it still runs smoothly