There are processes that you might need to run frequently. I gave an example above: showing the output of a Python script on your shell prompt (e.g. mercurial status).
Funnily I did exactly the same -- rewrote parts of a powerline (shell prompt status enhancements) implementation that I used and was written in Python, and turned it into Go.
But it still has to call into Python to get my mercurial status (we use mercurial at work so I need to have that).
