It doesn't actually require a config. You can set the binding on the command-line when you launch it. Anything you can represent in a config file with Tmux (set -g prefix C-o) can be expressed on the command-line.

Furthermore, in my opinion, both the defaults (C-a, C-b) are bad, as they conflict with default readline key bindings for cursor movement.

Ability to run `tmux <command>` in the terminal and have it affect the current tmux session was a huge feature for me. The other was actually being able to understand and write my config file. You can get somewhat far in Screen without writing any config, but I wanted some small tweaks to optimize my workflow. For example, a more vim-style way to navigate windows, easier splitting of panes, the new prompt on a pane split to be the current working directory of the pane I was on when I triggered the split, easy ability to swap the location of panes, etc. It's not prettified at all since I'm the only (intended) user, but my tmux.conf if it's helpful to anyone: https://gist.github.com/FreedomBen/9c52a6fa1543689798a8a42b6...