I use it primarily for its split pane functionality. Invaluable if you need to see multiple things happening on the same machine at once. I work in data science and often have several long running jobs on a single server, a notebook server, htop/iotop, nvidia-smi, or simply just having different panes cd'd to different directories - with iterm you can organise to a single terminal tab for each machine (including local), or group tabs across machines if they are for related work.