I'm not sure why the author advocates job control (ie ctrl-z/fg/bg) instead of using tmux/screen. A multiplexer offers far more flexibility, and most importantly does not lose state even if your session ends (eg ssh connection drops).
With tmux I'd need to create a new pane, navigate to the same directory, and reinitialize any environment stuff like virtualenv.
Use both! :)
Just kidding, tmux for life.